Yamaha DTXpress/DTXplorer/DTXtreme

Daniel:
Here's my take. I think you'll find the DTX to be well worth the 
money. As for applications, you'll find it very useful for practice, 
and in some situations, more than acceptable for live performance. 
However, I personally feel you would be doing your students an 
injustice teaching them on an electronic kit of any kind. Many 
students do no have a kit at home, and the only time they get to 
spend with a 'real' set of drums is that precious half hour every 
Wednesday night. There are too many subtleties that one most learn on 
an acoustic kit that just can not be done on the DTX.
Get one for yourself. You'll have a ball with it. But continue to 
teach your students on good old fashioned acoustic drums.
My opinion.
Stephen