Here is my $0.02 worth...
I'm not a professional photographer. I am into photography because I enjoy the challenge of trying to create visually interesting photographs that are of the highest image quality I can. I'm improving all the time in composing, camera control, and post processing. I've thought long and hard about Raw vs. Jpeg and here is my view:
Raw files are essentially like negatives from film days. I can use the same negative to print a bunch of different versions of that captured moment. A favorite quote of mine, from Ansel Adams: "The negative is comparable to the composer's score and the print to its performance. Each performance differs in subtle ways." I believe this still holds true for Raw and Jpeg which are like negative and print.
If all I ever wanted from my new 5D3 was raw files, I wouldn't need all of the camera's features for white balance, picture styles, sharpness, contrast, etc. However, it does have those features and I want to use them. I think the 5D3 does an amazing job at it and I really like the results most of the time.
So, based on those things, I like to shoot Raw+Jpeg whenever possible. The only time I typically shoot Jpeg only is when I need the higher burst rate and longer sustained burst I can get from dropping raw out of the equation. I look at Raw+Jpeg as a way of getting my "negative" while also producing a quick "print". In fact, my workflow includes separating the Raw and Jpeg images into two distinct areas ("raw" and "processed") before I even start post processing the Raws.
If I've used the features well on my camera, I'll get some pretty good initial "prints". In fact, there are many times that I will post process a raw only to find out that I like the jpeg from the camera better. There is often a certain quality to the OOC jpeg, that I can't quite put my finger on, and I can't reproduce in post. And, if I can get quality I like without post processing, that's cool for me. The only thing that sucks is when I see an OOC jpeg that I like a lot but think I can do better, only to find out I've wasted some time trying to improve it but later decide the original jpeg was better.