I'm using Shrook and have:

Friends - various people I know and a few I don't but can't fit elsewhere

Tech - Register, Ars, Gizmodo, Googleblog, etc

Mac - MacCentral, MacMinute, IMG, MacOS X Hints, Perversion Tracker, and so on

Culture - Metafilter, Plastic, Memepool, Boing Boing

News - Guardian Unlimited, BBC News, Yahoo News

Opinion - Atrios, TPM, Calpundit

Freeverse - people who blog at my office or friends thereof

NYC - Gawker, MTA service advisories

Thrilling, I know.