go sit on some bikes at the dealer, done be afraid to sit on everything you see, thats what they are there for.
the CBR600RR will be the fastest 600 that you can get, it's also the smallest.
If you REALLY think you will get into riding and stay into riding, i'd jump for a 1000+
the R1 is a very nice bike as well as the GSX-R1000, then you get into ZX-10's, ZX-11's and even Busa's and ZX-14's.
yea you'll get people saying you don't need a 1000 for your first bike, but unless, you buy used, the second your new bike rolls off the floor it depreciates by a few hundred at least.