I've been using Canon cameras for a long time, a good 15 to 16 years, my first was a EOS650, quickly followed by by an EOS 5, that was joined by the brilliant EOS 3 soon after its launch. An EOS1N and an EOS1V have also graced my camera bag, that 1V was just the best 35mm film camera I think I ever owned. All gone now, except I managed to pick up a 1N off ebay a few years ago, in mint condition for £100, and I still put a few films through it every year.
My first digital camera was a Canon D60 just as I went freelance, and just as digital was starting to take a slice out of the film camera market, £2000 at the time and just 6 megapixels on an APS-C chip, it served me very well for three years. I still have it, it still works, but it hasn't seen professional action for a very long time. I bought a Canon 1Ds MkII about 6 months after it was launched, I was lucky to get one at the time as they were rarer than hens teeth. I just happened to pass by a local camera shop in Chester and cast my eye though the window, as I usually do, there it was, £5000 worth of loveliness waiting for me. The camera had been ordered in months before apparently, but whoever had ordered it didn't want it in the end, my good fortune. I snapped it up there and then. This camera has shot everything from portraits to product shots, cars, vans, buildings, it's always produced the right image quality, even now that it's getting a bit long in the tooth.
So now I've moved on again, finally, to the 5D MkIII, 22.3 megapixels, a good 6 megapixels more than my trusty 1Ds, and HD video, I'm really very pleased with it, handling and build quality are great, that big screen on the back is just amazing, at least coming from the small screen I've looking at it is. The 1Ds is going off to have a new shutter fitted soon, so then it should be fine as my back up camera for a good time to come.
For all you Nikon owners out there, yes I used to use Nikons, my first was the tiny EM, FMs followed and F3s, but when autofocus came along Nikon were struggling in the catch up game and Canon were winning at the time, it wasn't an easy decision but I switched. I still have an EM and an FM with a few lenses, they still get outings when I'm in the mood to shoot film, but my investment in Canon glass has me tied to their cameras for the moment. Who knows though what will turn up from the camera companies over the next few years to tempt me away from Canon, those Fuji X series cameras look very tempting at the moment...