I would think something with complicated lyrics that you think you know, but you sing it really loud when you're drunk and you get the words all wrong. Like, "in the garden I was playing guitar...I kissed your lips and broke your heart"
Vertigo and The Fly are awesome when you're drunk. And, while I haven't tried it yet, I'd imagine Lemon would sound swell, too.
Oh, and above all others, Pride. I remember once after I'd been drinking, I was in the living room blasting Pride screaming "IN THE NAAAMMMEEE OF LOVE" when my mum/sister walked in.
Oh, and did I mention I was jumping/dancing around with a blanket tied around my neck like a cape at the time?