Like Foo Fighters? If so, check out Beehive Candy where they're sharing a recording of the Foo's playing at the Reading Festival and on Later With Jools Holland.
The Midnight Cafe has a Kings Of Leon recording from their 2008 (also known as the year before soccer moms & teeny boppers discovered KOL).
D&P's Bootleg Tunz World has an interesting 2004 They Might Be Giants performance from Austin, Texas.
Fan Made Recordings have been super busy lately; they're sharing audiences recordings of recent concerts by Lily Allen, The Decemberistists, Joanna Newsom, Cat Power, Ladyhawke and Editors.
Music-hole also has a tone of great recordings of Nelly Furtado, Lady Gaga, The Yeah Yeah Yeahs, Julian Casablancas, LCD Soundsystem, Daft Punk, Led Zeppelin, The Who and Joy Division.
For all you FLAC/loosless snobs out there; QualityBootz has a Counting Crows soundboard recording from 1994. Actually, if you prefer looseless recordings you're probably not visiting MCOM.