I guess what this really comes down to, is wether you (ninjaboy) want to go the serious stunter way, or do you just want to pop a few wheelies now and then.
If its just about a few wheelies than any 600 will do the trick. If on the other hand your going the serious stunter route, then it might be wise to pick up something a few years older, that is common enough for replacement parts to regurarly show up on ebay. You will need them. for some reason hondas (wether the 954 or the f4i) have a dispraportionatly large ammount of spare parts floating around.