need an aggregator

So, I've decided I finally need an aggregator to read all my web pages, instead of wobbling around the internet wasting time during the day. What programs do y'all recommend? Is there any way to subdivide the content within the same program, or do I need to set up separate aggregators (i.e. one for knitting, one for funny, one for political junk)? Please tell me what has worked for you in the past...

Also:

Stitch and Bitch tonight. Come on out, wouldya?