if u know how to play piano n u got $2000-3000 to drop then definately Triton or Motif.
if ur just gettin into beats and lookin for sumthin to trigger sounds in a basic computer software program like Fruity Loops then all you need is a midi controller.
MIDI Controllers
If you're just a begginer then i would just get a midi controller. If you're really picky about sound quality you can get instruments that are near identical to hardware like the Triton or Motif using VST plugins, which u can download free off Kazaa, in combination with software like Fruityloops or Sonar 3.
__________________
<B><font size=4 face="still time"><A href="http://www.soundclick.com/bands/2/21stavenueproductions.htm">21st Ave Productions</A></font></b><font size=5> / </font><b><FONT face=gunplay size=4><a href="http://www.soundclick.com/bands/7/knockoutzcru.htm">KnocKOuTz</a></FONT></SIZE></B>
<FONT face="bankgothic md bt" size=4> Exclusive Beats for Qualified MC's</FONT></SIZE>