You can have all their studio albums, but if you could only have 1 non-album release on top of that (either a single, an EP or live album), what would it be?

I'd go with In Rainbows Disk 2 because the songs on that are almost as good as anything from the main album, and it's nice having 'more' studio stuff from the same sessions of a 10 track album which is a perfect album, but one you can't help wanting a bit more of.

The Street Spirit (Fade Out) single is a tempting replacement choice as it's basically a 4 b-side EP including the essential Talk Show Host and Bishops Robes, but then again the other 2 songs are a bit boring.