Do you have friends that ride street bikes? Any kind of riding is more fun with friends IMO. Even if you do get a street bike, just the fact that you are having a hard time deciding, you'll want a dirt bike too. Do you live in an area with good places to ride offroad? Would you get an MX or a dual sport? For me, riding on asphalt is fun, but it get's old, and you're breaking the law frequently if you push a road bike at all, unless its a 500 or less and that means tickets. At your age, insurance is going to be very expensive as it is. Put a ticket or two on top and I'm not sure where that will put you.
A DRZ is a great compromise. I've got one with a set of street rims/tires and stock rims with street legal knobbie so I can go back and forth. It's a blast to ride around town, but not excessive. It's great offroad, pulls strong with an FCR and it's dead reliable.