High 30's seems doable, given the right conditions. Mr Kite has hit a few of those tanks. Those are best tanks. Seems the average (if you put some effort into it) will be high 20's low 30's.

452 mi @ 36.2 mpg
552 mi @ 37.1 mpg

11011011

Best commute RT = 27.5mi @ 90.5 MPG (sg2)
Best (non-trivial) tank = 665.5mi @ 72 MPG (fcd)
MPG Centurion - Hybridfest 2007 - Prius II - 26mi @ 106 MPG (sg2)
Dan <11011011> @ CleanMPG.com