I think most of use here started with that or a similar module. I myself used to use the Alesis DM-Pro, and still do for some gigs that need that less nuanced, totally machine-sounding groove.
I also used to like the EM-U Planet Earth module, though it was far more difficult to program. There are also a plethora of Roland, Yamaha and Alesis modules and drum machines to be had on the cheap on eBay. If you're going for realism and expressiveness though, skip all that and start researching software based approaches. For a plug-n-play experience, consider the Zendrumdrive.