MPG is a deceptive measurement, though - 1 or 2 MPG worse when you're getting 20 is much more fuel than 1 or 2 MPG worse when you're getting 40. This is why gallons per 100 miles is a better way to go. (For expansion on that, look
here.)
So, the 2009 2-wheel drive hybrids were rated at 4.8 gallons/100 miles city, 4.5 gallons/100 miles highway, and 4.8 gallons/100 miles combined.
The most efficient non-hybrid 2009 Chevy pickup, period, was the 4-cylinder 4-speed automatic 2WD
Colorado, at 5.6 city, 4.2 highway, 5.0 combined.
The most efficient non-hybrid 2009 Chevy full-size pickup was the XFE (with a 5.3 liter and 6-speed auto), rated at 6.7 city, 4.8 highway, and 5.9 combined. The 4.3 liter (with a 4-speed auto) got 6.7 city, 5.0 highway, 5.9 combined.