I recommend EZ Drummer or Superior Drummer 2. Both are from the company Toontrack. EZ is a cheaper, scaled down rompler. Superior is just
that, as far as all the things you can actually do with it. That's half of it though. The other half is how well you play (via MIDI edrums or from a keyboard) or how well you program the drums on a piano roll (or step sequencer) with the mouse. The key to real sounding drums is having a dynamic drum track. You don't want machine gun-sounding repititions happnin' during rolls/fills. So, varying velocities of each drum note/piece in a track (without getting to crazy with quantizing) and a good drum rompler such as EZ Drummer/Superior Drummer 2/Session Drummer 2/BFD 2/or Addictive Drums is a great way to have real sounding drums in your tunes.
I like use and love Cakewalk's Dimension Pro. It's got awesome samples/synths for use with MIDI keyboards/controllers. It's got some great Hammond Organ sounds that you might really like too.
I use an Edirol PCR-500 which is a very reasonably priced 49-key MIDI-controller keyboard with aftertouch capabilities and such. I've had mine for about a year and a half and it's never disappointed me. They also make 36-key (I think) and 61-key models too with the same exact interface.
If you have access to other applications, I'd recommend getting ahold of Cakewalk Sonar 8 Producer. It's the one I've had the most experience using...and it kicks ass. It also can knock a few birds out with one stone for you. It comes with the full version of Dimension Pro (complete with a few free expansion packs), Session Drummer 2, and loads of very useful, and powerful plugins. Plus, it comes with tons of different synths other than Dimension Pro that are quite nice as well.
I hope that helps.
Good luck!
P.S. Did you ever receive my email I sent to you regarding the "shredding collaboration?"