I think an RM 85 or 85L would be a good decision. The RM 85 itself is larger than the other 85s, so it should be a perfect size for you, but you might want to go with its bigwheel brother, the 85L, so go to the dealer and try it out.
If you are going to be riding occasional trails (even though these bikes really arent designed for them), they would be easiest with the Suzuki (or even the Kawasaki, since they are basically identical) since the bike seems to have smoother powerband in the lower end range, and the bike wont be so hard to handle in the twisty trails to control, and the better throttle response will be down there.
oh.. And you would smoke your friends TTR 125's and such with your 85 btw.
One bike I would also STRONGLY consider is the Kawasaki KX100 if you have your heart set on a Motocross bike (which I think you want, and would have the most fun on, since they really are a hell of alot of fun, expecially 85s) - Only problem, if you 'do' plan to eventually race, then it might be harder to find a 2-stroke 100cc class, so you would have to do so in the 125cc class, so you would be underpowered there.