Re: How do you respond to "Why Canon over Nikon?"
I've got a similar approach to the OP; I got into Canon because they had the affordable system back in the day. If I had to choose a new system now, I'd probably stick with Canon for reasons of ergonomics.
What I tend to tell people who ask which camera they should buy is to a) read some reviews and then b) go to a store and see which cameras feel 'right' in the hand, because honestly, in real world terms, I don't think there are really significant, major differences between the big brands. I just don't gel with Nikon's control layout. And camera bodies come and go, differences for prints and web use (what most people use this stuff for) are negligible, and I know I can't pick out what pic was taken with what camera in a blind test under most circumstances.
5DII | 300D | 30D IR | 17-40L | 24-105L IS | 70-200/2.8L IS | 100-400L IS | 15 FE | 35L | 50/1.8 mk I | 135L | Sigmalux 50/1.4 | Sigma 105/F2.8 Macro | C/Y Planar 50/1.4 | C/Y Distagon 35/2.8