I’m just trying out Feedlounge through the 3-hours demo account. It’s very impressive – it’s basically NetNewsWire in your browser window. It works beautifully with Safari, you can import your own OPML files, add tags to posts, etc.
I discovered Feedlounge by following links to this Textmate theme. I don’t think I’m going to pluck down the $5/month subscription fee, but I definitely see why you would want to 😉