Since then I've replaced a 50D body with a second 5D body, replaced the 400 f/5.6L with a 300 f/4L IS and sold the 17-40 f/4L and 100 f/2.8 macro. I've also added a Canon Speedlite 430EX II with a Gary Fong Collapsible Lightsphere.
I've also decided to keep the first generation 1.4X extender in order to have one for each of the "white" lenses, just in case. Here's a picture of the current kit, minus items like filters, remotes, etc.
|Powershot G11, Speedlite 270EX w/ omni bounce, ISO 500, f/3.5, 1/60 sec.|