I went for a GSXR 600 K5 for my first bike. More than enough power and handle really well. Ive now got a GSXR 750 K6 and thats just the perfect balance in my opinion. I personally dont like the thou's and can ride my 750 much quicker. The average rider will not be able to get the most from a thou on the road, and its almost always too much round tighter sections. Once you get going on the straights, then maybe, but the majority of the time a thou is just not necessary on the road. Id rather ring the nuts off a 750 and get there as quick if not quicker. It really depends on your riding style at the end of the day. I like to keep the revs high and be up and down the box for a more involving ride.
Many people own thou's purely to say they have the most powerful bike blah blah blah but 95% of them wont actually 'need' one, and thats why they seem very suprised to see a less powerful back up there backside.