The grAss is always greener on the other side!!!
I was Nikon for 8 yrs, got envious of the colour redition of Canon compared to the D2H, jumped the fence to Canon for the 1D mk111, and landed in a massive pile of cow *****!!
After 2 years of lies and hassle from Canon, I switched back to Nikon 3 months ago. No regrets.
Canon kit included 2x MK111 (awfull), 1x MK11n (excellent) 40d (didn't perform for me), 600 f4 IS (excellent) 400 f2.8 IS (excellent) 300 f2.8 (excellent) 35-350 (excellent) 70-200 f2.8 IS (was never happy with it) 24-105 (excellent) 17-40 (excellent) 10-22 (excellent)
New Nikon kit includes D3x (excellent) 200 f2 VR (stunning -the sharpest lens I have ever used) 105 macro (excellent) 16-85 (very good for what it is) 14-24 (excellent)
There are lots of excellents there, but I have been happy with a lot of the kit.
Pros for Canon - the lack of mechanical parts to damage between the body and lens, picture colours seemed (and still do seem) slightly more accurate, Joe public see white lenses as "pro", I thought IS performed better than VR, the AF on the Canon seemed to hit the target faster than Nikon (but then failed to deliver in the case of the MK111) the lens hoods on the long lenses are easier to put away due to the position of the tripod collar, the AF points are spread further compared to the full frame Nikon, the cross type sensors are spread wider accross the frame than Nikon,
Pros for Nikon - I find the controls easier to get to, I can change the shutter settings without taking my finger off the trigger, the cross type sensors are designed to work beyond f2.8, AF is more consistant than MK111 (but take a fraction longer to aquire) but most importantly - NIKON WORKS!!!!
I hope that helps,
Gary
Staff edit - removed some of the borderline sales text - any sales conducted here should be done via the classifieds forum, thanks