Roxanne by The Police. I don't like the song; it's just an excuse to scream like a jerk and butcher the high notes. Great in groups.

Angel Witch by Angel Witch (from the Angel Witch album, of course). The chorus is really catchy, and it's extended at the end. Also great in groups.

Bloodstone by Judas Priest. No other song puts me in a good mood like this one does after a pint or two.