Depending how much you want to get into sound design, AD2 can manipulate the daylights out of a stock drum sound. Similarly AD2 can be fed with any MIDI track or step sequencer, so pattern modification is often quicker that way.
Barring the above, AD2 has a lot of kits/patterns available, but in the long run "tweaking" tends to be quickest (just has a learning curve with it).