I've been an Olympus shooter for about 18 months or so, using first an E620 & 70-300mm lens and now an E30, 50-200 SWD & EC14 teleconverter (EFL 580mm). While I've really enjoyed shooting and learning with this gear, I feel like I've come to a crossroads with my photography.

I'm ready to make a significant investment in some good quality glass, but unfortunately with all of the speculation about the future of Four Thirds systems, I'm not willing to spend several $1,000s on an Olympus lens.

So, I'm considering making the switch to Canon.

My research has led me to the 7D, which by all accounts looks to be a pretty decent birding camera. While researching lenses, I've basically settled on the 100-400mm L IS USM lens. My main subject is birds, and while I've read very good things about the 400 f5.6 prime, I live in a forest/bushland type area, with a few good reserves with quite tame birds, so the versatility of a zoom lens is a must. I figure this will be a decent combination to produce quality bird images while I learn how to use the new Canon set up. It also enables me to lust after a 500 f4 & 1.4x tc combo for the future.

Questions:
Will the Canon 430 EX II be a sufficient external flash for bird photography?
Any monopod recommendations for this combo?
Which backpack would you recommend for this set up?

Any hints/tips/links for settings etc for the camera/lens/flash combo to really get the most out of this gear?

Thanks in advance