cbr's are front heavy compared to R6 and gixxer. If you are first starting out don't go and buy a 600 -- they are a lof of machine and are well capable of going 250+ you can get 100km's in first. They are no slouch.
get a smaller 250 ninja or something around that size. I would just hate to read that you spend a boat load on a bike (600) and dumped it. That's what the 250-500's will do.
And don't get me wrong a 250-500 is no slouch either.
Just dont go out and buy one of these canam sled looking bikes.