In some respects, a web-app RSS reader (like Bloglines or Google Reader) is better. You can access your feeds from any computer, the read/unread status is kept synchronized between PCs, and the centralized web-app arrangement makes more efficient use of network resources. Better to have Google Reader poll a site every 30 minutes than to have 10,000 Firefox installs each polling it every few hours.
The only browsers I know of that ever had good in-browser RSS readers were Opera and Seamonkey. But even in those cases, RSS was included as part of the mail client, not shoehorned into the browsing paradigm.