I spent a little time writing a little utility for Geany for navigating quickly between a given list of files:
http://www.milliwatt-software.com/jmg/files/geany_project_browser.py.bz2
I originally wanted it for navigating between already open files, but since I didn't at the time have an easy way to see what files geany has open (gah... I'm so lazy I haven't gotten around to installing Jeff's Lua plug-in yet), I instead just made it show files listed in a ./<foo>.project file that you create.
Just posting about it here in case anyone finds it useful. It'll probably only be interesting to folks who don't like taking their hands off the keyboard. :) While its running, I just Alt-Tab over to it, hit a key (or a few, bouncing around between files), then Alt-Tab back to Geany.
Let me know if you think it's handy.
---John