When someone ask whether he/she would get a dual or quad processor, the answer is get a dual because it runs faster in games or get a quad because its better in video encoding or software are still not optimize for quads...
 
Its true most softwares are still not optimize for quads for slowly they are getting there...
 
But OS are optimize for multi-core...especially in a desktop environment..sometimes when I'm not playing games or after playing games, i just minimize the game and surf the net usually have 15-30 tabs in firefox...while also listening to music..not to mention the anti-virus & firewall in the background..after surfing the net, I just minimize it again and go back to my game..
 
So for me, or for people like who like to do everything on a PC and jump for software to another, be it at games or surfing the net, or video encoding and you don't want to notice any slowdown, quad is really helpfull..
 
I really notice the difference in doing many things at once in my PC w/c is a C2D and my bros C2Q...we have the same specs...except for the processor..his rig is smoother to multi-task, no hiccups..unlike my C2D...

It really depends on who's using it. For most gamers, dual core already packs enough power because they usually don't "mega task" (15~30 tabs in FF? That's insane!). Games nowadays also don't take significant performance hits if you only have a dual core. With the exception of Supreme Commander, most games only benefit 2~10% in FPS by going quad. With the money you saved from getting a dual core, chances are you can have a higher end GPU, which will likely increase overall performance and quality.
 
It all comes down to, what are you doing with your computer. If you do video editing, encoding, and mega-tasking (30 FF tabs for instance), quad core would be your better bet. However, if you're only using it to type some word documents, surf some websites, and game, it is more likely that you won't see any significant benefit by going quad core.
 
As for your "mega-tasking", I really wonder if you run too many tasks for the computer. I currently have 5 FF tabs, with WMP playing music, and an IM program, but I only use 4% of my CPU power, running on an underclocked 1.33Ghz C2D. I also have both firewall and AV running in the background, as well as Google Desktop. IMO, you really should take a look in your task manager to see if there's any unwanted program running.

You can watch the processor spike when you open a window or program though and that I think it is where it comes handy.... It will tear through whatever it is doing at that point then it will settle down yes. I have a new E6750 @ 3.7Ghz right now and will be getting a new Q6600 G0 this Thursday and will tell you if I see any difference in speed on my system, and my system is as fast as any out there besides my GPU but, I still have a pretty fairly ovrclocked ASUS EAX1900XTX so.. I will be getting a 3870 here soon.

Having both comparable C2D and C2Q systems (QX@3.6 A/C) I can say that I will never go back to using less than four cores. Dual is nice, but when I'm flying around doing a bunch of different things I can (occasionally) see a bit of a stutter. On the QC system (x64 with 8GB) everything flies. Never a hiccup, stall, stutter, etc. It's so fast I think it knows where my mouse pointer is heading before I get there. The click and completion of the task seem simultaneous.
 
Today's games and apps may not take full advantage of four cores, but tomorrow's certainly will. Since the Q6600 is only a few bucks more than comparable C2D processors and can run at 3+ on air all day long it really seems like a no-brainer.

I would go with quad for tomorrow's games and applications.

I have the Q6600 OC'd on 3ghz on air stock fan. And it runs like a dime... It's so stable and smooth. I'm pretty much amazed with the multi-tasking handling of the Quad. Virus scan, music, gaming, surfing. And with the G0 stepping it runs very cool! 20-25 C idle... wow... I used to have a single core 2,66ghz and ran 50 degrees constantly... It was like a heater for my room. Glad I bought it.

I have a quad.  Or did have until I knocked Booze into my system last night  I'll see how that goes later.
 
However,
If you are editing large photos, Editing video or doing any sort of 3d work get a quad.
 
Current games wont use it, but I have AV and a firewall running + loads of other crap so its all gets used. I'll need a dual quad chip soon
 
Future games will need it.
Games in 2 years will think a Q6600 is too slow.
 
 
 
 
 
 
If you are playing games

 
Crysis is ready for quad-core.  I believe there are a few others too.

EdzBourne you said ''the answer is get a dual because it runs faster in games or get a quad because its better in video encoding or software are still not optimize for quads... ''
  -that is not correct.
 
Even for games a quad 2.4GHZ will be equal to a dual @ 2.4  
once there optomized for 4 cores however the quad will own.
 
The real question is how much money you want to spend because clearly a 3ghz quad is VERY expensive... but it will definatly equal a dual core at the same clock speed.

Errr... I think running 30-50 FF tabs has to do more with how much memory you have available to run smooth, rather then how many cores you have.  
 
To me, multitasking is actually getting more things done at one time, while perhaps playing a game, rather leaving certain apps like a browser minimized.

 
the memory is 2GB...and the memory used was only 1.3GB in the task manager....so basically not the memory...

 
  . o O (?)
 
okay.. I use FireFox.  Just his page alone on FF with all my other stuff is using about 644MB.  Now when I open over 30 Tabs, my memory jumps to 722MB used.  Thats basically 78MB more memory used.
 
So, I'm not exactly understanding what your disagree with.  If you have 4 cores, but have 512MB of ram, anything is going to run choppy.

 
Dude I thought Id never see the day when a stinkin web browser woudl take up 3/4 GB of freakin RAM. Doesnt anyone know how to code anymore! Dang!

Heh... I was just trying to contrast one thing.
 
If you have plenty of RAM, then you really won't notice that much of a difference, single, dual, or quad for a web browser.  I mean... I don't know any web browser that takes advantage of more then 1 core..  
 
But ya, the more tabs open, more RAM used.

Crysis actually doesn't benefit from a equally clocked quad vs a duel. On a quad the game runs the four cores at 30% or lower, with the rare spike up to 50% during mass physics. This has been reported by many at crysisonline, and incrysis forums. Also I haven't seen benchmarks from reputable hardware sites that prove otherwise either. A duel core does run the game close to 100% at times, so you see the game has sufficient CPU power with even a duel. It is badly GPU limited at this point.
Soo few games run better on a quad core, and so few are even planned for this year  I hate to disappoint you quaders here, but this is kinda like when 64bit CPU's came out like the Althon X64. How many years did it take before we got those chips used to their full potential? Now I don't think multi cores will take as long to be better utilized, but to even say--- "We'll get plenty of quad core optimized games this year" is misleading when non of those games will really need more then a duel core...... Yes Crysis is optimized to use a quad, but the lie is "it will run it better then a duel core can" ----not true!

(edit-- the games right now that do benefit from a quad vs duel, is Supreme Commander and Unreal Tourny 3, but the difference isn't earth shattering in UT3)

By the time we get games that use a Q6600 to a point that the E8400 looses badly, we'll have 8 cores, and the Q6600 will be poor at playing games that properly utilize an octa core. It is a possibility..... Of course it is more likely that games won't properly need or use octa until years after it's arrival either lol.
So buying a Q6600 to future proof yourself?.... It's a gamble! Is it the best odds? maybe..... My strategy- Buy a duel core now, and save up money for a "real upgrade" with nahalem or something later. Games and quads aren't married yet, thus this year will really come down to what ATI and NV release in regards to hardcore gaming needs.

But yeah, if you like to have 15 browser windows open, video encoding software running, virus scanning working, crysis running in the backround, all while watching a movie, sure a quad is going to be MUCH better at that then a duel..... But who the hell needs or wants to do all that at once?  I'd rather save money on my electric bill, as a 4ghz E84 duel is plenty for my needs.  

It really is about money... Quad is equal to a dual in some things and better for a lot.
 
(canadian)
$329.99
Intel Core 2 Duo E6850 Dual Core Processor LGA775 Conroe 3.0GHZ 1333FSB 4MB  
 
$1,149.99
Intel Core 2 Extreme QX9650 Quad Core Processor Yorkfield 3.0GHZ 1333FSB 12MB
 
-If you have the cash QX9650 is best....end of story.
-If you only game = E6850
-game + multitask + everything else = QX9650
 
I personaly believe in Q6600 for now, upgrade later.

I can't wait for some Q9450 benchmarks that either prove it is an amazing OC'er or a terrible one....  That way I can finally decide on what to get....

 
Grieve, dude, let's have this conversateon on Monday when the Wolfies are out. The E8400 will smoke the E6850 and the curent price on ncix is lower. And lets forget any Extreme chip as their just for milionaires and showoffs.