Be Yourself, Your Time Has come - Audioslave
Kryptonite - Three Doors Down
I won't be obscure:
1. American Pie - Don McLean
2. That Old Time Rock and Roll - Bob Seger
3. Rain on the Scarecrow - John Cougar Mellencamp
Hmm.. can't think of any absolute favorites.. but these are good:
Bohemian Rhapsody - Queen
The Reason - Hoobastank
Here Without You - 3 Doors Down
Embers and Envelopes - Mae
Etc..
Stairway to Heaven is overrated, Bohemian Rhapsody is overplayed, American Pie is called the best song too often, and Hotel California just isn't good enough to merit the "best" song. Personally I don't think you can measure the best of anything, simply because "best" is too opinionated to call one thing the best; there will be 99.9~% of the time at least one person who does not agree.
That said, I love the song Since I've Been Loving You. I can never get sick of it.