Who are the top UI designers on the web today?
callmeed: I've always been a fan of MetaLab's workI also really like what Sofa does:
http://www.madebysofa.com/
(checkout the enstore demo, epic: http://www.enstore.com)Ryan Singer of 37signals was very impressive when I saw him speak at RailsConf this year. I definitely think he's up there. 
http://twitter.com/rjs