Saw Alexisonfire at GIAN, they were pretty disappointing. Looking forward to seeing Rise against and Gallows. Rise against are the one band I haven't seen that would pretty much complete my list. And Gallows are pretty much a must as apparently they're not going to be around for long.
Best bands I have ever seen live are probably AFI or Dropkick. Special mention to Muse for getting me backstage tickets to their gigs, but as I have seen them more times than I can remember I'm not going to include them.