I had a similar problem at a certain point in time. As a matter of fact, I even asked a question here about it, but for some reason I can't find it now.
Instead of my own, I was trying to save contents of other people's blogs, for safe keeping. And it basically comes down to this:
- you can use google reader in offline mode (with gears) <-- haven't tried
- you can use feed demon to save blogs locally <-- tried, used for some time, then gave up (was too hooked up on google's "way of work")
- you can use the firefox extension called FireShot, which can save the entire page (not just what's on screen) as an image file <-- this is the option I've been using and am really happy with it (however, I do not save my own blog, so my demands in archiving probably differ from yours)
If you do find any better solution than feed demon, do let us know in here :)