Mozilla Rules
I'm not using an aggregator just yet (because, like this weblog, I'm holding back until I create my own... sooooon). But I AM using Mozilla's awesome "Tab-Group Bookmarks" feature which basically opens up a folder of favorites all in one window with a tab per link. I've got everyone in the JavaBlogs section of my blogroll in one and I can just open it up and flip through the tabs one by one. The sites I want to respond to or read more in depth stay open, but the others get closed (quick middle-button click). It's working out really well to keep up with the blog list on the left.
-Russ