There's a lot of very biased information in this post... so I'll add a little of my own.
Start off small and learn to ride. If you are looking for a sport bike, I highly recomend the Ninja 250 as a starter. You can find one cheap ($1000) in perfect condition or new for a little over $3000. Ride it a month or so and then sell it and upgrade if you want. But that bike is not too small for anyone, only to small for someone with adequacy issues and thinks that a bigger engine gives him a bigger dick. It is a very forgiving bike and can be very fun to ride. And its veyr light, weighs like 305 lbs (unlike the tanks that HD puts out). The newer 600's are well, bikes on crack; they are still very light weight 380 lbs or so but a ton of power (I have an 03 R6). Yes they hit their power band at around 6000 rpms but they have more power below that than the Ninja 250 does at all. Just from putting it at full throttle they'll wheelie in 1st or 2nd gear when you hit 12k rpms(or so, I'm not really looking at the tach when that happens). But they only get 40 mph give or take, but they aren't designed for gas mileage, they're designed for performance and handling and they are very veyr good at it.
What I would suggest is an SV650. While I haven't ridden one, I've only heard good things about them. They are a little toned down as they are a V twin, but that doesn't mean you can't have fun on them, and they are a more up right seating position. Not that any sportbike is bad, if someone says their wrists hurt from riding a sportbike that's because they are putting all their weight there which you shouldn't, you should be able to hold yourself up.
And my favorite quite about the good 'ol HD's: HD, the most efficent means of turning gasonline into noise and vibrations without added side effect of hoursepower.
Do your research, there's a ton of motorcycle boards out there, look aroudn a few.