What's your preference, all things being equal? I prefer MP3s myself (192kbps is OK), and I suspect from all the FLAC-related questions this week that most people simply want to convert the FLAC downloads to MP3 anyway.
I did a brief side-by-side comparison of the Saturday show in AIFF and 192kbps MP3, and the differences were extremely minimal. There's a bigger difference for studio recordings, but to my untrained ear, 192kbps MP3 for live audience recordings is quite sufficient. Some of the shows that I've downloaded as 128 MP3s are shitty, though, so I've sought those out on smithstorrents just so that I can get a higher-quality conversion.
128 kbps is what you'll get if you buy from iTunes.
I know; that's why I don't buy anything that I really care about from there. They're starting to up the bitrate, though.
Erich Mielke
Since I'm too lazy to look up who this is, fill me in.