Seems like all the cool kids these days ride 29'ers.
And if you're REALLY cool, you ride a rigid, singlespeed 29'er.
I've heard - but have not first hand knowledge - that the steering/handling is more sluggish on a 29'er.
I'd love to try a REALLY cool bike...but my LBS says "Try it first. You may not like it." So if they're lending, I'll be trying. But I guess I won't be buyin' before ridin'.