Looks like you've got for this base system
http://3xs.scan.co.uk/ConfigureSystem.asp?SystemID=1015
Ok let's take this appart
Case: Silverstone Fortress FT01B-W Tower Case Black
Older but still such a nice looking case, if I could afford it I would get one.
Motherboard P55: Asus P7P55D-E Intel P55 Express
Again cannot really fault this
CPU: Intel Core i5 760 Quad Core 2.8Ghz 8Mb Cache
nice, no complaints, maybe look at the i7 870 depending on cost.
EDIT:looking at the costs I'd say stick with the i5 760
CPU Coolers: Prolimatech Megahalems Super 6 Heatpipe Tower Cooler
Wonder if Scan's 3XS add a fan to it or run it fanless? not sure I'd like it fanless.
For that cost a corsair h50 might be worth looking at.
Overclocking: Intel i5 760 professionally overclocked by our 3XS engineers to 3.8-4Ghz. (i7 860 870 clocked at 3.6Ghz).
Now this I'm really not sure about, the reason being that the Asus TurboV software and Auto tuning should be able to hit around 3.8ghz, it'll take about an hour but it does it all for you and does it well.
http://www.guru3d.com/article/asus-p...-review-test/9
However I see it's 0 added cost, I wonder if the 3XS builders are just running the Asus Auto tune?
Memory: 4Gb (2x2Gb) Corsair Dominator PC3-12800 (1600) CAS 9 XMP
Again fine
NVIDIA Graphics: 1Gb EVGA GTX 460 SC 763Mhz GPU 336 Cores 3800Mhz GDDR5
If you want to go the nvidia route, this is probably the best all round card they do atm, oh and a very nice EVGA card which still carries their 10year warranty.
Power Supply Unit: 550w Corsair VX Series PSU
Good solid PSU for the reuirements, not over speced
If you want Modular ask about a Seasonic M12-II 520W Power Supply or even the Corsair HX520w or just ask and let them recomend.
System Drives 3GB s: *Drive Not Required - Using 6GB s or SSD See Below*
System Drives 6GB s: *Sata 6GB s Hard Drive Not Required*
Solid State Drives: 64GB Crucial RealSSD C300 6GB s Read 355MB/s Write 70MB/s
Storage Hard drives: *Storage Hard Drive Not Required*
Mistake, an SSD is nice, but a 64gb on it's own without additional storgae and you'll fill it up very fast.
Add in a 1TB Samsung Spinpoint F3, 7200rpm, 32MB Cache
You'll want to add in a hard drive as well, also that write speed seems rather slow for an SSD.
The 60GB Corsair Force, Sandforce SSD, Read 285MB/s, Write 275MB/s is a better option
Optical Drive 1 - DVD Blu Ray: Pioneer DVR-S18LBK - DVDRW
Personally I prefer the LG or samsung DVDrw drives I find them less noisey
If you do want options not on the list just ask for them, scan are good that way.
EDIT:Although I do agree with george1979 on Build it yourself.