I've been reading a lot of back-posts at Jan Heine's blog and now I wish I had 650b wheels! His research has led him to state that a 650b wheel with a 38-42mm tire is a perfect blend of speed, comfort and handling but a 700c wheel with a 38-42mm tire is simply too big in diameter and the handling characteristics are lost. I've been devouring the Rivendell website and Grant Petersen's writings since November but now I'm more intrigued by Jan's stuff. He's a committed Randonneur and his research and writing is slanted toward that type of riding but it's all pretty transferable to a fitness cyclist like myself. Both guys emphasize comfort on the bike but Grant is all about utility and Jan is all about performance. Even though I'm a super-clydesdale, I want to squeeze every bit of performance possible out of my efforts.