I use a Dell Inspiron 1405. I Run Linux on mine so there is no gaming going on. For everyone to know now, if you plan on running Linux on any laptop you buy, Please stay away from Dell. There laptops are great but there on-board wifi cards are really hard to get working without knowing the proper drivers ahead of time.
Although if you plan on gaming on a windows laptop why not go with the XPS?
I have had some time to play with one a buddy owns and it's not bad. He actually replaced his crappy desktop with it. But then again he only plays two games, Counter Strike Source and World of Warcaft (btw WOW tolly pwns TICHONDRIUS FTW). Do yeah in my opinion Dell Laptops + Linux = Big headache, but Dell XPS laptop + Windows XP = Good time Gamming.