deals, the sv was mentioned by Z (how could he not, he's biased anyway)
one thing to keep in mind for all newbies is the power versus skill.
just because you can ride a 600 doesn't mean you can ride well.
go for some track days and you get a good idea of how many better riders there are than you. I ride a 954 and have been "beaten" by smaller bikes all the time. these guys (ands girls too) have bikes that are perfectly suited to them.
i've had an old 400 go around me on the outside while i'm scraping the deck. the other guy was smaller than me and had is bike on full throttle were i couldn't go full throttle.
so having a big bike may be "cool" and make you feel good but if you can't ride it to at least 75% of its potential, why have it. you'd have much more fun on a bike you can ride well.
in reality, a 600 is the most power ANYONE could ever need (except for idiots like me). so why jump straight into it?
here's one of Z's links that should be in this thread
http://www.sportrider.com/ride/