Boy thats a tough one bnhonest. I would probably say Michigan was the most important. I know Michigan turned out to be crap, but I think it got the kids convinced early that they can play with anyone and believing in themselves. They improved throughout the year obviously. Michigan had big lineman and I know their fanbase felt we had no shot especially with the intimidation of playing in front of 108,000 on opening day.
As far as the best teams and most exciting wins. That would have to be the two come from behind victories over Oregon State (who had beaten USC the week prior) and #11 TCU. Here are the clips of those come from behind drives.
[ame=http://www.youtube.com/watch?v=IR5lN9W8fs0]YouTube - Utes score 11 points in 90 seconds to beat Oregon State[/ame][/url]
[ame=http://www.youtube.com/watch?v=4O7Atnr8c_4]YouTube - Utah Football vs. TCU 2008 (Final 3:00)[/ame][/url]
They were both very exciting games to be at!