I bought the 15" low end, (despite some research). I thought it would be more than enough for games anyway. (need laptop as I travel quite a lot, and would be good to play stuff while in hotel room).
I just figured it wasn't worth the extra £250, or whatever it was (got a 10% employee discount)
After more and more reading on the forum, and checking out specs of some games, it looked like 256Mb on the Graphics card was the current minimum spec for a CoD type game.
Given that it's a lot of cash, and I really only want to buy a computer this price every 3 years, I decided it was worth getting the high end so at least the graphics card would give me some future proofing for the next couple of years.
So cancelled low end order, and bought high end.
Am sure low end would've been enough, but felt that I could be kicking myself this time next year, so was worth it.
If you're not a gamer - don't think it's worth worrying about...