For build quality and general quality Lenovo is the best, hands down.
Sonys look nice, but they're really really overpriced for what's inside.
Dell tends to be a bit overpriced but sometimes you can find a nice deal.
HP is the best insides to price ratio right now. The external build quality isn't always the greatest, but they're dirt cheap for what's inside. I bought an HP dv5t for $600 when I found a 30% off coupon. And it seems like every couple weeks there's a new 30% of coupon.
Asus is also known for quite good build quality and they usually have great internals as well.
stay away from acer, gateway, and compaq. lenevo is good, but not as good as IBM used to be. sony looks cool and a solid build, but they are expensive when it comes to whats inside. i'd get an Asus or like a Dell studio. i'd just wait until Dell has a sale, i just bought a new dell that was 400 dollars off but its canada only.