A sketch blog could be a good idea. You'd be able to put everything up while still being able to tag stuff like sketches and full pieces separately. Then on days when you just want to blog, that's no problem. All in all, while FA and DA have those abilities as well, you'd be free to combine what's on multiple accounts down to one. It'd make uploads easier to keep track of, mostly.

Also, it'd be up for a full custom site design, so you would have to stick with a site's perma-layout and change it up when you want to. That's the good thing with personal sites/blogs.

The problem might be where you'd have to upload the pictures themselves. For a blog, you might have to go through an upload client like Photobucket or Imageshack. I dunno, I've not been on a blog for quite a while to know if anything's different nowadays. What would worry me is the frequent art swiping from upload/host sites. If it was more of a personal site at Freewebs, that would be a direct upload where everything would be hosted locally on the site storage.

</shutting up now>

I use Imageshack for mine since Photobucket has a bigger reputation for screwing people over. The entire gallery on there is set to private, so I think I'm safe in that respect.
I have up my blog on LJ now and so far there's a couple of entries. I have it set up pretty well at the moment, at least until I get bored enough to really put a lot of effort into its layout and whatnot.