Honda Magna 750 VF is a nice fight in the cruiser/crotch rocket niche. It's got the get-up-and-go of a sport bike (0-60 in 4, redline at 14k) and the relative comfort of a cruiser. I'm 6'6' and 220 lb and I fit on it comfortable. It's been a GREAT first bike for me... I took the class last year too and have about a season and a half so far on it.
Only cost me $3400, so you shouldn't have to break the bank. A motorcycle mechanic told me not to get below '90, simply because they're a lot harder for mechanics to work on with so many variations. Motorcycle standardization has come a long way in the last 10-20 years.