I've been a road cyclist my whole life, but I bit the bullet the other day and ordered a Marin 29er MTB from my local dealer, based in part on Monte's recommendation. Based on the Marin size chart, for my height, I got the 20.5" frame. I should have it in about a week. I tried ordering one this past summer, but they were all sold out for 2009. Apparently, they make bikes over the winter and, once they're gone, they're gone. (No mid-year production.) I can't wait to ride it! I plan to ride it on the road when the weather is a little too sketchy or cold for me to want to ride the road bike, and take it off road whenever I get the chance. At the track, it will be my pit bike. Talk about an all purpose bike!