I'm suprised nobody has mentioned "Wonderwall" by Oasis. Wonderwall and "The World I Know" by Collective Soul were the first two songs I learned. Wonderwall uses simple chords but was great strumming practice. The world I know uses a few unusual chords, but they are very easy and the intro/chorus is played between the first and seventh fret, which was a great change of pace at a time when barre chords were too hard and open chords were getting boring.