Hi all,
After five years my laptop simply can’t handle it anymore therefore it is time for a change.
So after much thought I have decided to build my own desktop computer to a specification that fits my requirements and pocket.
It would be appreciated if you guys could look over my spec and give me your opinions. Things to bear in mind are that it is being built to handle a mix of general computer/business use, gaming(quite a lot), downloading, video watching and the like.
In my list there are multiple choices and this is simply a matter of availability/price so an overall opinion on all compnents would be great.
Also, bear in mind I do have the ability to add 17% to the total value of components(would rather save it than spend it) since I can get it tax free in San Marino. So, if there needs to be any significant upgrades just give me a shout.
Here's the list:

CPU:
Intel Core 2 Duo E6400

Motherboard:
Gigabyte GA-965P-DS3P(rev.2.0 or more recent)
Gigabyte GA-965P-DS4(rev.2.0 or more recent)
ASUS P5B Deluxe Wifi

Graphics card:
Sapphire X1950GT (maybe a Nividia?)
Sapphire X1900GT?

Memory:
Corsair TWIN2X2048-6400C4 2Mb kit 800Mhz (C4)
Corsair VS2GBKIT667D2 2Mb kit 667Mhz (C5)
Kingston KVR667D2N5K2/2G 2Mb 667Mhz (CL5)
Geil SKU#GX22GB6400DC 2Mb kit 800Mhz (C5)
Geil GX22GB5300LDC 2Mb kit 667Mhz (C5)

Hard Disk:
Seagate ST3320620AS 320Gb, Sata2, 16mb
Western Digital WD3200KS 320Gb, Sata2, 16mb

PSU:
Enermax Liberty 500W

DVD Drive:
Samsung S-182M DVD/RW
NEC 7173 DVD/RW

CPU fan:
Zalman CNPS9700LED
Thermaltake Blue Orb II

Monitor:
Samsung 920N
Samsung 940N

Now I was talking to a salesman yesterday, or rather my girlfriend was because my Italian is abysmal, and he was saying that it might/would be a mistake to mix an Intel chip with an ATI graphics cards simply because of the recent AMD/ATI merger.
He was also saying that he would reccomend having an Crossfire/SLI configuration, 2 hard disks and bigger (than ATX) case for airflow?
I didn't say anything at the time but I was thinking 'how much?' and that it was just bull sales patter.
Was he speaking the truth.
Cheers.

Doesn't look like a bad build at all. Selecting stuff from any range of parts on your list should end up pleasing you.

Regarding the sales person: I am almost 100% sure that he is either an idiot or just trying to "sell" you on some more expensive stuff.

I think he is rong,
I had my x800gto running on a amd4000+ san diago @2.92ghz and it ran just fine.

Then i upgraded to a c2d e6300 and it screams along. Its all preference really imho. Intel is faster right now. Only thing i see rong is your power supply.
Enermax makes super nice stuff also but pc power and cooling are the shiz when it comes to powersupplys. Its 50$ more but its rock solid with 5yr manufacture warranty.
http://www.newegg.com/Product/Prod [...] 6817703005

Either psu will work, id like this one though.

Without comparing the prices of the products you listed & whether you're overclocking or not, I'm suggesting these.

A link to the e-tailer would help.

Thanks for the input fellas.
Akhilles,
I will possibly be overclocking in the future, as the need arises, but as of now I will hold off until I'm more up to speed with all this stuff.
As far as listing retailors etc I think it would be a bit meaningless since they are all in Italy and that list is made up from about 10 or more shops.
The prices are in Euros and of course it won't be a straight comparison because the prices have extra costs factored in such as shipping, import duties, sales tax, profit margins etc which are different to the US.
Not to mention if I buy from San Marino, tax free state, that just throws everything out.

Thanks to all, it's seems I got things right first time.

Don't bother with CrossFire/SLI......the sales guy is trying to make more money off of you. Your setup doesn't warrant dual cards at all, you're getting ripped if you do.