I have a few of the Groove Monkey sets here, also quite a few of the EZX expansions. But you can do quite a bit with just the basic set that ships with EZDrummer, as David mentioned it is very easy to tweak the existing patterns to add or remove hits.

I've used it exclusively for a year or so. I really like being able to split the drums out so that each piece of the kit is on a separate track in my DAW, makes it very easy to have separate processing for each piece.