To me, the 29er makes sense for taller people as yourself. There are some disadvantages to the 29er, (slower acceleration, weaker wheels), however I think the proportionality and the benefits outweight the negatives for taller people.

Gary Fisher makes some good bikes, I personally don't like their geometries for my style of riding, but they are good bikes.

My only concern with a Niche bike like the 29er is finding parts over time. Fork selection is limited, Marzoochi and White Bros. are the two "quality" fork manuf. making 29er forks. Tires would also be more limited.

I'd say "Go For it!"

L8R