Life expectancy of 2004-2007 VW Golf?

I am considering buying a 2004-2007 VW Golf with 30,000- 50,000 miles on it. I have heard many great things about the gas mileage and length of life of the vehicle. What can I REALISTICALLY expect in terms of average fuel economy and how many miles the car will last for, this uming regular oil changes and maintenance. Thanks