[Always good to have some of these in your quiver][link]. None of them are really competition for the (still) king of web icons packs, [FamFamFam’s Silk icon set][silk], which is now over 3 years old.
[link]: http://webdesignledger.com/freebies/the-best-free-icon-sets-of-2009 “The Best Free Icon Sets of 2009 | Web Design Ledger”
[silk]: http://www.famfamfam.com/lab/icons/silk/ “FamFamFam lab: Silk icons”