CPU: 7/10 - Slow for a gaming system, but cheap.
M/B: 3/10 - Asus stuff is poor quality, and that's a very low spec board
RAM: 4/10 - 2GB is not enough for a gaming PC. At £45 for 4GB, having less is inexcusable.
PSU: 6/10 - Most CM units are very loud, and the GX units are relatively mediocre. 750W is also ridiculous for such a system
GPU: 7/10 - The GTS450 is a reasonable card, but the HD6850 at £144 makes it a little overpriced, when the HD6850 is a full 50% faster.
ODD: 10/10 - The drive I use
Case: 10/10 - But I only really recommend such a case to top-end systems, not entry-level budget gamers like this, as they're not necessary for cooling or space.
HDD: 7/10 - OK as Samsungs go, but Samsung are not a good hard disk brand.
It will all work, but there are some pretty poor choices here.
You're spending £488 here, plus nearly £20 on delivery due to using two stores, summing at least £505.
This comes out at about £615 delivered, a bit more expensive, but it's in a completely different league to the system you posted. It doesn't use terrible quality parts, it has ample memory, the graphics card is much faster, and the CPU is also much faster.
