Homebuilt vs Pre-Assembled

Hi all;
I'm in dire need of a new system and for a few days have been looking around trying to decide on parts etc for my new PC;

Needed was a new case, MB, Processor and graphics card.

The aim was to create a high end gaming (in time for Crysis 2) /work (Compiling Basic Java/Word Proccesing etc) system that had some room for upgrades but was unlikely to need them for a few years yet.

I decided on a 1366 socket board and i7 950
along with a GTX 580
and HAF X casing

This priced up at around £1015 (bit over $1800),
with me using old parts as well
(i.e. a Hitachi HDT721010SLA360 ATA Hard Drive, a basic Disk Drive, a 750 watt 'High Power Plus' power supply, 8Gb of RAM over 4x2Gb, monitor etc)

On the site Novatech that I've been using they also have some builds of their own
For example the iRule Gaming Build pricing in at around £1130

Now looking at it this build has a lot of what I'm looking for, a GTX 580, an i7 950
along with some things I hadn't thought about upgrading, disk drives and hard drive (was next on the list)

However it uses their case and as far as I can tell a somewhat generic motherboard (can't seem to find a brand name in the specs for it)

So my question is this, have I stumbled upon a bargain for what I'm looking for or is it too good to be true and I'm better off going back to looking up parts?
Any help is appreciated and needed, also on the parts I've picked if there is a better build ppl can think of.



For this let us assume that my budget is around £900 and £1130 is a bit of a push.