This post was largely written by Ryan Stewart, a guest blogger on Read/WriteWeb. I've added my own Best of Breed picks for each category.

Feed readers can be divided up into two general camps: The web based feed readers - such as NewsAlloy, Rojo, Bloglines and Google Reader - are mostly powered by Ajax and provide a basic, if unspectacular, list of features. However if you want to read your news outside a web browser, having your feeds stored within these web applications becomes problematic. The other camp is the standalone feed readers which include FeedDemon, RSSBandit, and NewzCrawler. They provide a lot of power, but are tied to a single computer. Unfortunately, I have yet to see a true Rich Internet Application feed reader which would provide the best features from the two camps and bolster mainstream RSS usage.

Web Based Readers

The current generation of web based feed readers have done a great job of using the web to make reading feeds a more social experience. Many of the web-based RSS readers allow users to rate a particular news post or tag a post so that it is more meaningful to other users. As a result, users of online feed readers can benefit from their peers and have a sense of the most relevant items. Rojo takes this a step further by allowing you to have "friends" that you can share posts between. However at the same time, when a user comes to rely on their favorite web based solution, they give up some control over their content. Services like Google's Reader are almost always available, but the smaller companies can have issues with downtime during maintenance or periodic disruptions.

Richard's Best of Breed picks:
Rojo is my current favourite, although I still have issues with its relative lack of speed. Bloglines is a good solid choice, but lacks the advanced social functionality that Ryan alluded to. A Techcrunch review late March by Frank Gruber rated Google Reader and FeedLounge highly for performance.

Desktop Based Readers

The desktop solutions have a different problem. They offer powerful feature sets such as synchronization (allowing you to download your news to read later). However most can't provide the social aspect of the web based readers. They provide the users with a familiar user experience, which will be key to widespread adoption of RSS, but they can't provide the closeness to the web that the web based readers can. The desktop readers handle enclosures very well, which as RSS matures will become a very important feature. The ability to play music or watch video directly from the RSS feed is something that right now is possible with the desktop readers but has rudimentary implementation by the web based readers. The desktop readers all provide a solid tool set with an experience that most users expect and are familiar with.

Richard's Best of Breed picks:
Newsgator leads the pack in my opinion, mainly because of its synchronization functionality. Newsgator has a second-to-none suite of RSS Reader products, covering all the major desktop platforms - Newsgator (Outlook plugin), FeedDemon for Windows, NetNewsWire for Mac, plus its other specific solutions. I can also recommend BlogBridge, a free and open source desktop reader. I've been testing Blogbridge over the past couple of months and found the smart feeds (basically custom searches) to be especially useful.

The Rich Internet Application Reader

Ideally, a news reader built as an RIA (rich internet app) would take the best things from the Web and desktop - and provide all of the benefits. It’s important to realize how valuable a quality user experience is to the average person. The ability to give that user experience in a package that also leverages the power of the web, is what sets RIAs apart. An RIA news reader provides the power of the desktop reader, but without the install. It can also incorporate the exciting social aspects of the web based readers. Because RIAs can be deployed on a variety of platforms, the user has absolute control over their content. They can read the news on their PDA, on their laptop, or on their cell phone. The ability to download content for use offline would be a big part of the RIA - and while online, the user could take advantage of tagging and seeing what their network of friends is reading. Nothing stands in the way of desktop applications implementing these kinds of features, but with an RIA the user isn't tied to one computer. The goal is to give the user access to their data at all times, regardless of how they want to consume it, and then get out of the way. Therein lies the elegance of the RIA solution.

Richard's Best of Breed picks:

As Ryan noted, there doesn't appear to be a market-leading RIA RSS Reader at this point. In many ways Ajax-heavy web-based RSS Readers would fit into this category - so I'd nominate the likes of Google Reader and FeedLounge, as well as apps like Goowy that use Flash. But like Ryan, I don't have an overall top pick in this category - perhaps people can make suggestions in the comments?

Ryan's Conclusion

The ability to deliver desktop level functionality is something the web has been attempting for a long time, and we're getting closer every day. News readers are becoming more and more indispensable as people turn to blogs for their news - and even major news sites are making increasing use of RSS feeds. Being able to take that content wherever you go - online or offline, is going to become very important. The explosion of mobile devices and the coming of the living room entertainment system are going to provide new ways for users to consume RSS. The solutions that are going to get the most attention are those that can deploy on any of these platforms and also provide the '2.0' functionality that has changed the web.