Cheap Little-Known College or Expensive Well Known University?

It's almost time for me to make a decision on what college I would like to attend in the fall, and I'm torn. I got into McGill University, a very prestigious and respected school in Montreal, the problem is it will cost me and my parents about $20,000 a year (5500 of which will be in stafford loans.) On the other hand I got a full scholarship to St Edward's, a small liberal arts school in Austin Texas. I would still have to pay for room and board and travel expenses but I will be able to do that and graduate with minimal loans. I like both campuses but McGill is by far the better school with an international reputation. I know my problem is common for high school seniors and I was wondering if anyone would like to share their experiences or offer some advice. In particular, how much does the reputation of a school matter? I plan on majoring in economics but I'm not sure I want to work right after college. I would like to spend some time volunteering and it would be nice to not have to worry about paying off debt.