I have been facing the same question. I used a CBR 400 RR (Baby Blade) for a very long time. It was ideal for city riding, with traffic congestions. After trying the Yamaha R1, I knew the baby blade wouldn´t cut it anymore but the litre bike was also way too much. I decided to go upgrade my bike to the new 2006 R6. I tried it, and was quickly turned off by it. It was too much a track bike and didn´t provide to much comfort. The new 2006 GSX-R 600 by contrast seems a to be much more street oriented, and felt more comfortable to sit on. It also comes with a standard steering damper, and adjustable foot pegs for a more comfortable and personalized ride. The 750 has all that plus another 30hp, at a cost of only 2kgs of extra weight. I figured i will eventually need the 750´s extra power and decided to get it over anything else. (i can´t be bothered getting the 600 first, selling it and then getting the 750). If comfort is purely what u´re going for, you should consider a sport tourer instead.