I'm planning on buying a new laptop...?

I'm planning on buying a new laptop. I've had a toshiba (satellite) for almost four years and it's been pretty good so i'm inclined to stick with them but I'm open to suggestions. I need something light. I'm soooo tired of lugging around the heavy laptop I have now. I'm a student at Uni if that makes a difference. I like to download music and whatnot so it should have a decent ammount of space...help! Oh! and I would like to keep the price under $900.