I've previously blogged about inclue!, Attensa, Blogbot, and NewsGator. I've just stumbled upon two others, intraVnews ($), and RSS Popper (Free). Rss Popper even works with Outlook Express.
intraVnews looks pretty powerful, and even supports posting to your blog from Outlook.
RSS Popper seems somewhat basic (but really, how much flexibility do you need?)
Anyway, worth a look. So far, I still prefer NewsGator, even over the built-in reader in Outlook 2007 (which still seems a little quirky). Eventually, I'm sure I'll use Outlook 2007 exclusively, but it really bothers me that I can't export my feed list as an OPML file. I have over 100 feeds now, and adding them in all by hand would drive me insane.