Warning, RSSoterica and kottke.org sausage-making to follow. Matt Wood has a post up on 43Folders about how he groups his RSS feeds in Google Reader for easier reading. I use pretty much the same system as Matt, but with a few more folders. I have several folders for reading long-form blogs:

Always
Often
Sometimes
Pending
Food and Drink
Frippery
Infoglut

Always, Often, and Sometimes are self-explanatory. The Pending folder is for blogs that I'm trying out, Frippery is stuff that is non-kottke.org-related to be read during non-work hours (ha!), and the Infoglut folder contains a bunch of blogs that have a low signal-to-noise ratio and are too high volume to keep up with unless everything else is read (any multi-author pro blogs that I read (not many) are in here). For organizing non-long-form blogs, I use these folders:

Links
Yummy
Photos
Tumble

Links contains link blogs, Yummy has a bunch of stuff from del.icio.us, Photos are photoblogs, and Tumble contains tumblelogs, FFFFOUND!, and other Randomly Curated Other People's Images White Background Sites. And then for news, I have an NY Times folder, a Sci/Tech News folder, and a Keywords folder for Google News keyword searches.

All this folder business might seem overcomplicated, but I find that grouping feeds by mode helps greatly. And by mode, I mean when I'm reading link blogs, that's a different style than reading/skimming long-form blogs in the Always folder. Posts from link blogs usually take a few seconds to read/evaluate/discard while the Always folder posts take longer. If they were all lumped together, I couldn't get through them as quickly and thoroughly as I can separately. A juggling analogy will help -- Wait! Don't leave, I'm almost done! -- it's easier to juggle balls or clubs or knives than it is to juggle balls, knives, and clubs at the same time...same thing with different kinds of blog posts.