Go slow and small, buy used
The best advice I can give is if you've never ridden a motorcycle or it's been a few years then buy a bike no bigger than about 750cc's, and buy it used. Within a year, depending on how much you drive, you'll want to go bigger or faster and if you buy a new bike you may have a problem selling it and getting a fair value. There are a LOT of used motorcycles out there at a great price. AND take a certified motorcycle training class because it may save your life.