Yukon expected mileage 2009's

I'm going to trade my 2001 Yukon SLT this year on another Yukon. Wondering if I should wait for the 2009's or go with 2008. I've heard the 2009's will have better fuel economy. Is there a redesign coming for the 2010. My 2001 has been a very good unit, with 88,000 miles it's time for a new one. :)