If you are under 35 years old then a "crotch rocket" is tolerable (spine, wrists, shoulders) if not fun. Consider the 2009 and newer Yamaha FZ6-R. The R is a new model for beginners and Yamaha is tied with Honda for best quality.

If you are over 35 consider a "standard" bike or a cruiser like a Harley Sportster, Triumph, BMW or Suzuki cruiser...