I have very little motorcycle experience other than the MSF class and a 50cc scooter that I had for a year. I'm pretty comfortable on two wheels, have been a long-time mountain biker and now a road biker as well. I'm a mature 24 but have a reputation for having a bit of a lead foot... though I'm very respectful and borderline terrified of motorcycles so that shouldn't be a huge issue. I'm also in San Francisco so I feel like I need to be more cautious about the type of bike I'm buying than someone in a less dense area, or at least one less replete with near-vertical hilly stop signs.
So my question is, will I kill myself on an SV? Should I be concerned about getting a 650 to start, or are all the "you have to start on a 125cc or you'll spontaneously combust" guys pretty much dead on?
I have a beautiful 2003 in black lined up with less than 5k miles on it for $3500 with only a slight dent in the tank... having a hard time saying no! Aesthetically it's EXACTLY what I want and I hate the process of buying / selling big ticket things... would rather buy one bike and keep it. Should I be strong and go for the little bike?

Thanks!