Teleport Pro -- Offline Browsing Webspider
Blogger has an official way to backup one's blog. Problem is, it's slightly ridiculous and it produces a huge document.
I tried using an OS X personal spider (SiteSucker) to suck down my blogspot site, but it started failing with a download error after page 300 or so. So I located my ancient copy of Teleport Pro (windows, alas) and fired it up. It worked perfectly, creating several thousand pages and localizing all the URLs pointing to internal blogspot pages.
I'm impressed. Incredibly, you can still buy Teleport Pro at this site. It's not the most intuitive application, but it works great.
Update 11/25/08: I ran into a 65K limit for URLs when using Teleport Pro with the 2008 version of Gordon's Notes. There's a more advanced spider sold by the same vendor, with a $30 updgrade discount it's $165. I'm going to look around for alternatives. Also in 2008 Blogger did introduce the ability to export blogs in a Google defined XML format.