My mountain bike is a 1994 Giant ATX 760. I've converted it to singlespeed by using a White Industries ENO eccentric hub, which allows me to get proper chain tension for SS riding. I've upgraded the original cantilever brakes to Avid SD 5s and put on a riser bar as well. I run 175 cranks and a 40t Rocket Ring up front and a 23t White Industries Freewheel in the back. For a while I had a Truvative Stylo ISIS crank in 180mm, but I could never get the left crank to stay tight, so I'm back to a square taper bottom bracket
UPDATE: July 2005 Due to some recurring bottom bracket and drive train problems, I've retired this bike. Parts are being pieced out to other projects, or will be sold. I've replaced this bike with a Rivendell Quickbeam, which is more Road/Cross bike than MTB, but probably better for the riding I do. The Giant gave me 11 years of hard service.