this just may be food for thought, but I think the need for a certain sized bike can not only be based on the rider's desires and abilities, but I think it has at least a bit to do with the rider's physical nature as well. I know I will be corrected (and at the more advanced levels, rightfully so), but I believe that for most regular riders, the size of the person in question should have an impact on what is 'necessary' for them. My example would be Nick's 636. Being the size he is, he could slam the throttle on that thing and in a straight line, use up most of what it had to offer on any given day. However, at my manly 127lbs, that same bike would fly me to the moon. Unless I'm a racer of very decent caliber, I'm not going to need a liter bike to get my tiny ass moving. I've already seen my 600RR keep easy pace with 750's hauling large riders. If power-to-weight ratio is what makes acceleration fun, then the power should be chosen in proportion to the weight involved. I may never ride a liter bike in my life simply because I may never be good enough to require the obscene amount of speed a 1000 would provide to a little leather-clad garden gnome like me. That wasn't really an argument for or against the liter-lovers, I'm just tossing in my tiny two cents...