I was hoping to help someone over in the forums at Goblinoid Games with some GIMP and large scaled, hex mapped based map issues, but the being the GIMP newbie that I am, I could only really steer him towards Inkwellideas' sweet GIMP hex map brushes.
I'm a bit confuseth with regard to shapes and paths in GIMP myself, having stumbed over some possibilities recently with the one page dungeon contest map I submitted. I finally resorted to just quickly hand drawing and scanning the map I'd made. At some point I'll play further with it, but it's hard to break with my Photoshop 7 experience. This custom GIMP brushes tutorial might come in handy at some point, but Inkscape might be the better tool for .svg scalable hexes for mapping purposes.