On the topic of a post-Google Reader RSS world, and specifically regarding my choice of FeedWrangler, this explanation by Shawn Blanc of how versatile Smart Streams are in FeedWranger is fantastic. I learned quite a bit about them, and though I have some set up as "folders" like I had in Google Reader, I can completely see myself using keyword based Smart Streams and Filters for seasons of organization.
If you are also settling on FeedWrangler, you should definitely read up on Smart Streams.