I recently acquired a DR-3. It's a very capable machine. While I haven't been overly enamored with the preprogrammed patterns, the thing is totally user programmable...I've programmed my own patterns. You can also define drum kits, combine patterns into songs and stuff like that.
The dr-3 also has bass built-in as well.
The menus can be a little ackward, but if you're patient, it'll do a lot.