First time builder 2 - 2.5k budget. Upgrading from a 6 year old PC!

That's right, my Falcon Northwest just turned six. I've added some memory and replaced the GPU twice, but other than that I've not upgraded a thing. Aside from Sins of a Solar Empire (which I miraculously run at near-max) I haven't bought a new title in a long time.

So it's time for a change! Instead of another major road trip this year, I'm looking at finally biting the bullet. I've never designed a system from the ground up, and so despite my obsessive research, I'm sure I've made some poor decisions or at least decisions that could use some improvement.

I know 2.5k is a rather large budget, but my last computer lasted a long time and I'd hope that this one does the same. I'd rather spend a lot up front than upgrade every year.

As of now I play a 22" monitor (1680x1250) and probably won't upgrade to anything bigger for a long time. However, I do want the option of going bigger.

Now to the builds: I'm torn between 2x GTX 280 SLI and the 4870X2, and my builds reflect this. I'm not sure what my best bet is given that I'm only playing at 1680x1250. I also want this GPU solution to last as long as possible before upgrading.

Minor concerns listed below builds.

SLI build

PC Power and Cooling T1KWSR 1000w $270
2x MSI N280GTX-T2D1G OC GeForce GTX 280 $760
EVGA 132-CK-NF78-A1 LGA 775 NVIDIA nForce 780i SLI $200
Intel Core 2 Quad Q9550 Yorkfield 2.83GHz $325
CORSAIR XMS2 DHX 4GB (2 x 2GB) 240-Pin DDR2 800 $80
Harddrive WD VelociRaptor WD3000GLFS - 300 GB - SATA-300 $270
Antec 1200 $165
Optical $25
Vista 64 $100
=$2195


HD4870x2 build

PC Power and Cooling T1KWSR 1000w $270
HD4870x2 $550
DFI LP LT X48-T2R LGA 775 Intel X48 $240
Intel Core 2 Quad Q9550 Yorkfield 2.83GHz $325
CORSAIR XMS2 DHX 4GB (2 x 2GB) 240-Pin DDR2 800 $80
Harddrive WD VelociRaptor WD3000GLFS - 300 GB - SATA-300 $270
Antec 1200 $165
Optical $25
Vista 64 $100
=$2025

I plan to OC the CPU and would like to cool with external water. What's the best performance for the price given my level of expertise (which is to say, zero). Also, worth it to liquid cool the chipset if I'm already cooling the processor?

Everybody says to avoid DDR3 even though the step up in memory and mobo is only an additional $250 or so. IS there truth to this? Are the gains worth the expense?

Is the hard drive worth the expense? Would it be better to just go with a 7200 drive and save $200?

I'm iffy about going 64 bit, tell me it's going to be alright!


Please feel free to address any and all concerns as well as point out anything you feel I've missed or need be concerned about.

Thanks!

The performance differences between the Core i7 and current gen hardware is rather large in cpu-intensive applications. Also, with X58 boards they are implementing triple-channel for ddr3 ram, which should prove another good advancement- Not to mention crossfire AND sli capabilities on the same mainboard. Somebody went to say that Nehalem chips will do to Core 2, what Core 2 did to the previous generation of chips. Gutsy claim? I'd wait and see what the new stuff does to the market before spending this kind of money man.

The idea for me is to buy big and then not buy again for 2-3 years, so building a cheap machine now does nothing for me, especially while my current one runs fine.

As to whether or not I will wait for the Nehalem I don't know. I don't imagine it will hurt to simply wait and see, though I don't relish waiting another 1-3 months to build. However, if the difference is as great as you say, effel, it would probably be prudent to just hold off.

Whatever the case may be, how do my current builds look? Adequate for playing demanding titles (i.e., Crysis) at my native resolution with maxed settings? And can anybody take a look at my other questions? Thanks!