Other than the lie of the 17.5k red line, the new R6 lives up to the hype, from what I've heard on different bike forums. It does not have a very comfortable stance, but as far as straight race performance, its a champ! I'm a Yamaha fanboy, so I would say go with the R6.

I hear very good things about the Honda CBR600RR as just being a well balanced bike. The Kawasaki ZX-636RR is a pretty good bike from what I hear, but that is, again, from fanboys. The GSXR-600 is always what its hyped to be as far as power, but I think the actual manuverabilty and handling come down to the rider, and fanboys of Suzuki can usually handle their own. On the real D, you should go try out each of these bikes, I'm sure you can find SOMEONE that will let you try each of them--including a dealer. You're gonna have to decide which one suits you. The R6 is the narrowest bike you can get, period. Some people dont like that small feel, but to me, when it came to handling, it seemed like the R6 automatically did the turning, with little effort from me--this was after riding a friends ZX-6R. But he hates the small feel of anything Yamaha. So, like a said, find something that fits you and you WILL be happy!