webmonkey's Weblog Tool Roundup by Joshua Allen (2002) is an entertaining and fair overview of the different blogging options and tools.
Offline blogging tools
The aptly named Blog is a free Windows program that lets you post entries to your blog while you're off-line (they're added to your blog once you go online again).
Radio Userland is a Windows and Mac off-line blogging system that costs around $40 per year.
LiveJournal is an open source journalling system that works offline or online on all major operating systems.
The new version of Microsoft's popular HTML editor, FrontPage, is set to include features to facilitate creating blogs.
Web-based blogging services These are accessed via your web browser. The advantage is that you can access your blog from anywhere and don't have to worry about technical details. Disadvantages are that you have to be online to add an item to you blog and that your data lives on somebody else's server.
Blogger is probably the best known (free) blogging service with over a million users in early 2002. It also offers a paid-for version without ads.
LiveJournal is less well known, but is almost as big (and its source code is available for free should you want to host it on your own server - see below).
Pitas (aka Dairyland) is an alternative to Blogger. They are free but offer paid-for "pro" versions.
TypePad is a relatively new blogging service, but is based on the very well known Moveable Type (see "tools hosted on your own web server"). It is particularly easy to customize and has many useful extra features, but charges around $5 per month for the basic service, going up to about $15 for the 'pro' service.
The blogging network is an interesting commercial experiment. It offers a blogging service for a smallish fee, but also pays bloggers for their content depending on how often their blog is read. A typical (unpopular) blogger is likely to get little or no payment, but a few blogging superstars might make money.
Fotolog is a directory of photograph-based blogs and allows one to set up one's own free fotolog.
uJournal is a free blogging service (it was built using LiveJournal software).
20six is a UK and Germany based free blogging service - with additional paid-for services being planned.
easyjournal is another free web-based blogging service.
mblog is a free (I think) web-based blogging service based on Moveable Type. One of its many features is that it is possible to SMS an entry to one's blog.
Blog tools hosted on your own web server
Moveable Type and Greymatter are free blogging systems to install on your own server. Mobeable Type charges for more advanced features.
Project Steve Guttenberg is a free blogging tool that needs to be installed on a server, but requires only PHP and integrates seamlessly into any existing site.
Blosxom (pronounced "blossom") is "a lightweight yet feature-packed weblog application designed from the ground up with simplicity, usability, and interoperability in mind. " It is a free Open Source system.
Syncato is "power blogging for power users" with all posts stored as XML and searchable using XPath queries.
WordPress styles itself as more than a blogging tool - it's a "state-of-the-art semantic personal publishing platform with a focus on aesthetics, web standards, and usability". It's also free and open source and is seen as a good alternative for Moveable Type. It runs on PHP and MySQL.
Gblog is a more recent addition than most of the others mention here. It is free for personal use (licence for commercial use required) and runs in PHP (but no database is required) and it is apparently easy to install. It has exceptionally strong news feed (aka RSS or Atim feed) support.
Audioblog allows you to post sound files (e.g. voice recordings) to your blog for about $5 per month. They host the sound file and allow a generous amount of bandwidth.