It was more than a beer that did it... It was a period of time. Samuel Adams and Yuengling were always a winner. I was into the Canadian beers for a while...Moosehead, Labatts, etc... Then it was Pete's and Anchor Brewing...which then led to the craft beer movement. The rest was history.
This is pretty much the same for me, in college I was used to Keystone Light and Natty and Busch and all that crap. When we'd go out for wing nights in college, the bar always ran a special on Saranac Pale Ale. Everyone seemed to hate it but I really enjoyed it. (When we wanted something different we always got Moosehead or Labatts as well).
I remember always liking Sam Adams, and was introduced to their seasonal beers by a friend. I think that's what got me hooked, but I can remember someone usually springing for a case of Yuengling or Blue Moon. I think it just developed from there and I was so intrigued by how beer could taste that I would order something different everytime I went to a new resturant or bar.