Cheap gaming laptop for £550

1_What is your budget?
[b]£550 ish

2_What is the size of the notebook that you are considering?
15 inch

3_What screen resolution do you want?
Best for the money

4_Do you need a portable or desktop replacement laptop?
desktop replacement, but not too big.

5_How much battery life do you need?
Not important,

6_Do you want to play games with your laptop? If so then please list the games that you want to with the settings that you want for these games. (Low,Medium or High)?
Yes. Medium settings ideally.

7_What other tasks do you want to do with your laptop? (Photo / Video editing, surfing the web, playing music, watching movies, Etc.)
web, movies, music

8_How much storage (H.D.D Capacity) do you need?
At least 160gb

9_If you are considering specific sites to buy from, please post the links to them.

10_How long do you want to keep your laptop?
2 years minimum

11_If you would like to mention some other things about purchasing your ideal laptop, post them.

The situation is this, i'm moving to new zealand for a year but i dont think i can live without games for that long so i need a portable solution! Once i'm there it will effectively be a desktop replacement but it would be handy to be able to use it on journeys etc so dont want it too big. I dont need to run things at cutting edge graphics but i would like to be able to play modern games at medium graphics (Crysis excluded... i can live with playin that at low!) . Dont want to spend much more than £550 as i have enough to spend money on what with the move and all!!

12_Please tell us about the brands that you prefer to buy from them and the brands that you don't like and explain the reasons.

I have been looking at a dell studio 15, with a processor upgrade or possibly a xps 1530 from the outlet store. However i've been hearing bad press about nvidea 8600gt chips. No real reason to go with dell except that they're fairly cheap and customisable.

13_What country do you live in?
UK

Any advice would be helpful as this is my first laptop purchase. Many thanks.