When teaching, my students play my semi-decent Sonor acoustic kit while I play opposite them on my Roland TD-12.

Cost me an arm and a leg but was well worth it!

In the background to the left is my De Gregorio Chanela Cajon which I use for acoustic jams and behind the kit on the desk is my Fostex 16 track hard disk recorder which I use for recording demo's. The TD-12 plugs straight in which is great for not needing to use microphones on the old acoustic kit.