Get the Aluminum frame. It will last you longer. You won't notice a difference in speed between a 26" and a 29". As far as versatility. IMO, the 26" would win that battle. Along with the parts you mentioned, as far as a LBS carrying them. But I'm partial because I have a 26". And in 26 yrs its the best bike I've owned. Cro-moly is good and sturdy. But if you ride in the winter then go with the aluminum frame.