I've been using Firefox/Thunderbird on W$ for probably 6 months now, and I love them. The ad blocking in Fireforx is really good, and there is an additional plugin that makes it even better. Plugins have been a bit of a pain in Firefox and its predecessors, so make sure that you accept default directories and registry patches as necessary (in W$). This may be why some of you had problems on some websites. With more recent versions, it doesn't seem so difficult to get Flash and and Shockwave to play nice. Also, I've fornd that some ad-intensive sites (e.g., mail.com, Wired magazine) apparently have the graphics for some of their navigation buttons originate from the same domains as their ads. The consequence, of course, is that if your ad blocker becomes too effective at blocking their revenue source, it becomes very difficult to navigate their sites (birdy dastards!!). Tough to get to your mail when the folder has been rendered invisible by your own ad blocker (unless you've memorized the location). Thunderbird is much better than Outlook or Outlook Express, but I haven't figured out how to have it alert me when I've received mail.

I strongly support the idea of substituting Firefox and Tbird for the normal Mozilla.