Since you're looking for a basic MIDI keyboard I would recommend the
Edirol PC-50. It has a surprisingly nice keyboard and is VERY
affordable, yet doesn't have all the knobs and other clutter of most
controller keyboards. It does have a USB connection for computer use.
Connections come out of the side so it can be pushed right up against
gear. And it is simple and attractive looking:
http://www.edirol.com/products/info/pc50.htmlI have an Emu Xboard 25 which does have aftertouch and a nice-feeling
semi-weighted keyboard, but the overall appearance isn't great. A
49-key version is also available. If you're really into keyboard
"feel" this one is cool:
http://www.emu.com/products/welcome.asp?category=532Ivan