Proper, Full Backups

Hi, I need to fully back up my blog. It’s the compilation of 3-4 other blogs. It has over 500 posts and I’ve been posting on it for over 7 years. It’s been hosted by other services, changed domains, and I integrated posts from other blogs. It’s one big huge conglomerate blog of all my posts. I want to make sure all the articles/posts are FULLy backed up.

That said, the WordPress “export” feature seems to simplistic.

I do that and get a

wordpress.2011-01-13.xml overly simplified 8.8mb file. Is that enough to fully back up the blog?

It’s self-hosted.

Thanks.

Is there a way (although just getting it fully backed up in any ways is first priority) to backup a blog for local offline browsing (not as important as full backup. Thanks!