As I just posted in another thread, I just purchased an i3-380UM powered Acer Travelmate 8172T, a close twin to the Acer TimelineX 1830T.
I was comparing it with the Alienware M11x, but the Acer won out on price, size and weight.
The Alienware is actually in a rather large case for the size of the screen (Someone said it was actually capable of holding a 13.3" screen, but Dell opted for the smaller 11.6" screen just to say it was the first 11.6" gaming notebook. Whatever.) and the weight.
I travel a lot, and I want a lightweight machine, and the Alienware was noticeably and considerably heaver than the Acer.
And for some reason, Alienware chose to put only 10/100 ethernet on it, not Gigabit. That, by itself, is a deal breaker. I synch my notebook and desktop computers before/after each trip, and 100 "Fast Ethernet" just doesn't cut it! I did notice that the larger Alienware models do have Gigabit, it's just the 11.6" that doesn't. Go figure.
The Alienware was far sexier, but in the end, the Acer won out.