To fill my 40GB Toshiba I used pandora.com to find music similar to what I already listen to.
This is what is on my mp3 player now which I have playing in the background when Im flying via an auxiliary wire.
Ive gotten into a lot of European metal such as the likes of Hammerfall, Dream Evil, Jag Panzer, Iron Savior, Falconer, Edguy, Evergrey, Symphorce, elegy,
But I also listen to other stuff such as 12 stones, 3 doors down, avenged sevenfold, atreyu, 30 seconds to mars, ac/dc, guns and roses, alter bridge, angel dust, audioslave, beautiful creatures, breaking benjamin, default, disturbed, dragonfoce, die trying, forty foot echo, galloglass, hibria, hinder, kid rock, linkin park, nickleback, seether, sevendust, shinedown, slaves on dope, slipknot, three days grace, theory of a deadman, tool, and trapt.