I would highly recomend the Vermona DRM, Elektron Machinedrum and Jomox Xbase 999. They all compliment each other very nicely and would cover a lot of ground between them (synthetic, warm analogue, cold, huge sounding) - My personal favourite is the Vermona.
You can download 200 high quality sounds, sampled from the Xbase999, Vermona, Aribase99 and Mbase 11 drum machines at our website for 100% free:
Drum Machines 01 | Sample CDs & Sample Packs - Wave Alchemy
All of those sounds have been lovingly recorded through an API 512c pre-amp and will give you a great idea of the tones/sounds to expect from those drum machines. Hopefully this should help you make a decision on your drum machine purchase
Click the "free samples" tab to the right of the 3d image (next to 'cue in player') to get the free sounds.