I also vote for Dell. My first preference is a home-built system; you know exactly what's in the computer adn IMHO maintenance is easier, but you need all of the software and whatnot, and that may not be feasible for a laptop. My mom bought a Dell last year, and it's been working beautifully!
I also agree to avoid Gateway
and add eMachines and Compaq to the avoid-like-the-plague list...
Good luck!