I'm trying out an offline blogging client that runs on Linux (these things are not that easy to come by). It's called Drivel, and it seems to work OK, as long as you tell it that your WordPress installation is actually Movable Type.
Oh, and it looks like it only supports one category per post, and no native tags. Not very impressive, really.
Since I tend to draft in jEdit, I’ve often thought that what I need is a blogging plugin for that, and been surprised that it doesn’t exist. One of these days I’ll have to write it…
(ETA: tags added later via the web interface. Far from satisfactory, really.)
(E further TA: damn, it looks like this theme isn’t showing native WordPress tags, anyway.)