I have been having the best time just using my 5Dm2 for stills. I've shot Nikons for over 10 years and really like them for their ease of use and general sharpness. I was mostly using medium-fi glass and Nikon's basic SB28 flash.
Enter the 5D. I put it all in one lens - the Canon L series 24-70 2.8. Very sharp. I bought the 430 mid-pro flash - again, very nice. Now even if I'm just doing a quick snapshot at a party the images come out great. The product stuff I've been shooting for my wife looks terrific. Shallow DoF!!! I love the ISO up to 3200 (let alone 6400) and still holding a good image.
Basically it's just a great camera. I thought I would only use it for HD video... Nope. It's becoming one of my new favorite tools =)