Now that I've been commuting on the 2009 Suzuki GSX-R1000 for a few days I was able to log my fuel mileage on multiple tanks and averaging the two most recent gave me...
...roughly 37 MPG while commuting. That's great, considering I'm lane splitting most of the time and using the throttle to avoid the crazy people out to get me every morning and evening!
If went on a trip that was all highway I don't see why I couldn't bump that figure to well over 40, heck, maybe even 45 MPG!