If you're playing to an audience of friends and your Mum, they might like anything you play (for the first 3 songs, at least) but for a real, live, critical audience, you'll need some crowd pleasers. Here are some to get you going.
100 Greatest Guitar Songs (excel document 22kb)
Guitar Songs graded by difficulty level (excel document 105kb)
Songs by Chord Changes (word document 71kb)