A great midi controller for under $500.?

I'm getting into the whole "home studio" scene and I have a keyboard (older) but it's annoying with it's "touch sensitivity" I need to really hammer out chords and such to get it so I can actually hear it and it's hard to have everything sounding the same most the time. I just want a keyboard with many buttons and knobs to be able to really mess with my sounds. I don't really need built in sounds as I only really use vsts, so that's not important... unless it has some really phat pads :P then that's okay. I use the editing program Reaper, so, i don't know if there's any keyboard that would be good to use with that. I'd like to have a lot of keys, but, if the octave switch out is easy I don't mind a desktop friendly area fit..... thank you!