I used to have an Alesis SR16. Sisters of Mercy in a box! I sold it in the great I'm-about-to-become-a-dad-so-I'm-liquidating-the-rack-o'-synths-and-committing-to-only-stringed-instruments fire sale of 2008. I miss it, though, and am sort of interested in a simple beat machine that can be footswitched into fills to switch between patterns.
Before the Alesis SR16, I had a Yamaha RX-17. Man I can't believe I programmed two full length albums (well, cassettes) of metal/grunge/punk/post-hardcore songs, complete with fills, tempo changes, etc. manually into that thing through that tiny 0.5" x 2.0" LCD screen. Uphill both ways! Through the snow! get off my lawn!