I'm 6' and rode both a large 04 and a medium 05 Chameleon. The large was great for XC and trail riding. It felt pretty normal and if all I did was ride trails, then I would've stuck with it. The medium is great for street, dj's, park, and bmx tracks. However, I set the medium up w/ SS, 24s, and a rigid fork. The large had a z1, 26s, and 2x9 w/ bashguard. I did have 26s and 2x9 at one point with the medium, but it wasn't a good fit for me since I don't do as much XC anymore.
-ebRich