Sufjan sold out the Chicago Theater, which, for reference is really really huge and has been filled in the past by Conan (when he did a week of shows there) and Kanye West (when he shot a BET special there) amongst many other way bigger acts. Impressive.
Whilst I did not see Sufjan, I did see LCD Soundsystem and Hot Chip two nights in a row a few weeks ago. This was the third and fourth time I've seen LCD this year and the shows were even better. I honestly can't think of a better live act touring right now. If you like them at all, see them when they come anywhere near you. They're not going to tour after next year, so you'll want to see them before they stop existing.
The night after the two night LCD/Hot Chip (who are also great, by the way) I saw Sleigh Bells. They were decidedly less good, they played for a half an hour at 1:30am (it was a midnight show), and it wasn't very enjoyable. I like their record, but they don't really work live, surprisingly quiet too.
A week after that, I got free tickets to see Jonsi for the second time this year, and he was stellar, as always. Not as great as Sigur Ros live, but still really good.
This year I've also seen Broken Social Scene (very, very good), The Morning Benders (very, very good), Spoon (very good, but with sound issues
) and Phoenix, who put on the second best show I've ever seen (after the combined LCD shows). They played Wolfgang Amadeus Phoenix in full, in order, and did a long encore with some of the best of their back catalogue. They're another band you'd be crazy to miss if you like.