Yes that would be an added bonus but I actually never considered that before. The main advantage is knowing exactly how the code works so if you want to add any new features in it is a trivial matter. Don't mention the inline documentation though (there is none )
I'm yet to find a blogging solution that really scales well. Wordpress is nice, but as you add more plugins to it you end up putting a lot of SQL queries through each and every time you load a page etc., which can cause issues
MT is nice as well and has the added advantage of building static HTML files instead of relying solely on the database backend.
Typo looks like it could prove to be useful, though I've no idea what kind of footprint it has
I use Blogger straight for one blog, and use their FTP fuction to post to my server for another. I should perhaps move the Blogger over to my own domain, but I'm not sure what will happen with the archives that are reasonably keyword rich. Would Google think it's a mirror site?
Started (on my own domain) with some PHP news script years ago, used Greymatter for a good while then found wordpress which is what I currently use. Greaymatter was nice actually, but very limited.