I agree with the original poster. The 5D Mark II & I is much heavier than for e.g a Panasonic FZ38 bridge camera, in both body & lens, flash weight ie close to 2 kilos versus 454gms for a camera with a leica 27-480mm lens
Obviously there are quality differences, & DOF differences, if you need that on every single occasion.
I have 3 cameras that I alternate with. 1 of which is a canon 5D Mark I with a 24-105mm L lens + 70- 300mm + flash. I carry my FZ38 80% of the time, including holidays, because its lightweight. My shoulder aches after carrying this lot aroung in a large camera bag, even for a short while.Some people are also more intimidated with having a large lens pointed at them. On the FZ38, I have a huge lens range without needing to change lenses. Its good in low light & takes v good low light videos, which my 5D doesn't. The Manual & Auto controls are easier to use on the FZ38. Theres no Live View on the 5D & despite having been a no live view Non Digital SLR user before, I actually now prefer live view now for composition. I don't want to spend another 1700 Pounds to get a 5D Mark II body, with this feature & video, when I already have video on my FZ38. The high Iso is impressive on the 5D but I don't print above A4 much & I mostly distribute pics & video via internet , so noise isn't a massive issue. If photography was my full time source of income, then I would consider getting a 5D Mark II & selling my original 5D, but for basic photo oppurtunities it would still be overkill, so I would still have my leica v-lux-1 or FZ38 as alternatives. I don't always need shallow DOF ie large group wedding shots, where sometimes I need to crop couples/individuals located around the pic, as someone is smiling weirdly, spoiling what otherwise would be a good shot. With shallow DOF it wouldnt be possible.
Shorter primes ( which aren't really that much smaller than my canon zooms) wouldnt cover the focal range I use ie for wide landscapes & portrait shots, so I'd still end up carrying more than 1 lens with the body, or just the 24-105
I also carry the 5D less because I'm aware that others will be aware that I have over 2,000 pounds of camera equipment on me, with its distinctive Canon Branding & 5d badge (which people may think is the Mark II) . I feel like muggers bait doing street photography with it, so I now just use it for weddings or in inside/portrait photography. My 260 GBP, FZ38 suits most everyday situations for me & fits easily into my handbag or messenger bag. And it doesn't increase my inflight luggage weight that much.
Possibly its easier to carry for guys, or theres a very small proportion of DSLR users, who carry the large cameras, to look professional , but don't know how to use them. Some friends had a "professional"??? with all the 5D gear come in to do the staff website photos. They were all over exposed. The guy put the zoom lens practically in their faces , they were terrible pics, even ordinarily attractive people looked awful & washed out.
So in summary, its not always about the equipment, sometimes its the photographers skill that makes the shot & you can get v reasonable shots on a good compact without the bulk if you know what you're doing
elena
http://www.flickr.com/photos/40207062@N08/