www.igoogle.com
I like the way I organize various feeds by tabs, and then over morning coffee, I can use to Firefox to quickly "control t" (or "apple-t") articles of interest in a new tab.
To quickly navigate through the tabs, I simply use "control up / down" (or "apple-shift arrow"). And when I'm done reading and wanna close that article, I can use "control-w" (or "apple-w").
I slam through lots and lots of news that way!
(Slightly unrelated, but for certain types of OPML based feeds, I like to use Thunderbird's RSS reader)
Google reader is good for RSS (maybe even better in some ways), but I'm just sorta stuck in my iGoogle groove.
I also really like Yahoo! Pipes and how you can use it to quickly find all sorts of information scattered all over the place.
On the subject of Yahoo! Pipes, has someone at TechSoup considered making a Yahoo! Pipe mash of, say,
Techsoup RSS, delicious tags, and any other Techsoup-esque stuff?