A question you've probably answered a million times, but with the exception of ex-bands (My Bloody Valentine...) I think the only artist I'm really desperate to see is Cat Power.
Especially so after having tickets for cancelled Barbican show.
The Books would probably also be high on my list, closely followed by Deerhoof, Scout Niblett, Why? and Islands, maybe.

Who are yours? GO! And make me jealous with your stories of seeing the above bands.