Prius at 6 years old

With my 2004 Prius approaching 50,000 miles- I guess I do not drive much- I am still averaging just less than 50 miles per gallon through all seasons, and all driving types and road conditions. That beats the re-configured EPA mileage by close to 4 miles per gallon. From what I have seen, the 2010 is a lot more of a car with a lot more bells and whistles than prior generations. I would love to try out the new generation Prius for 2010, but my 2004 has quite a bit left in it and I feel lucky to have what I have at this point.