I've never ridden a 29er, so I can't speak to the differences. Conventional wisdom suggests that 26ers are easier to maneuver on tight, twisty singletrack, so I think it might help to know about the trails in your area. Don't limit yourself to WSD bikes by the way, especially if standover is not a concern. In looking at componentry, pay attention to the fork. Some bikes are definitely speced better than others in this regard at any given price point. Read reviews and look at the weight of the fork.