drums synths ... rack or standalone??

[dl4plm]

Maybe someone can throw some thoughts into this.
I am wondering how to build up some percussion capabilities in my home studio.
Sonar 7 Studio has Session Drummer 2 but to be honest apart from the few basic kits its not really what I expected. Not sure if you can add additional kits to get more synth based drum sounds ??? But ...
So my thoughts turned to something external ... perhaps an Alesis drum pro or the latest DM5 ... use Sonar to trigger it ... or should I aim for an MPC1000 or something like this ??
I am into electronic synth tracks ... so whats your thoughts.
What do some of you guys putting tracks together use??
Software or hw based??