There is quite a bit of room in the "sport bike" category for specific types of riding.
I have owned several big street bikes in the sport bike category. They were all a blast to ride in their element.
Generally, the bigger bikes (1000cc+) are a fun way to burn a Sunday morning, but can be tedious for commuting, particularly around town. My last bike (a Kawasaki ZX1000) was scary fast and could accelerate like the space shuttle (not as fast off the line as some, but the bike had a bottomless throttle and would pull hard in any gear at any speed). Mostly I used it to commute with..it kind of sucked around town in traffic. It was big and heavy (I'm 6' 1" and 210lbs) and got away from me twice at stop lights when I put my foot down in a greasy spot. It was fun though and would pull power wheelies in 2nd gear.
By the time I hit 40, the "crouching" position just wasn't that comfortable anymore and the bike started to sit in the garage more and more. Eventually, I sold it (and bought a boat, but that's another post).
Bikes are like shoes...easy to buy a pair that feel ok in the store, but hurt your feet like crazy after a day or two. Before you buy, think about how much time you plan to spend in that position. It also matters if you are out having fun, riding with your buddies or just putting in your time on the way to work.
The 650-750 size is easier to manage around town. I'm a big fan of the SV bikes from Suzuki. I think they are cool looking (not everybody will agree, for sure). I also like "dual-purpose" bikes. For carving your way through traffic, you can't beat agility.
Most sport bikes bought for fun, end up sitting in the garage after a month or two. I drove my ZX for a couple of years and then it started to sit....I felt a little guilty about having that money tied up in something that wasn't getting any use when the family could be enjoying it (if we did something else with it...that's how we ended up being boat owners).
Good luck! Post a pic when you decide.
