JPG -- every few months go by and I'll shoot a few hundred in RAW. Found it just doesn't make that much of a difference for me. THis is a RAW forum so you will most likely not get many that shoot JPG.
But if you believe everything you read hear ....
1. You'll only shoot raw
2. You'll make a JPG and DNG backup
3. You will process every image with DPP, Lightroom and then Photoshop (Both Legal and Illegal Copies)
And, when it is all said and done, you'll have the finest workflow that pro's will envy, except you'll never output any files to the web or print.
I know - I know it's a hobby ......Like Bodog said, if you are happy with your results it doesn't matter. I shoot Jpg and use only DPP and Picasa with a little GIMP thrown in for selective coloring or B&W. Folks at work are amazed at the images on my digital frame in my office. Enough to get me 1/2 a dozen gigs a year, including a wedding dress reshoot where the pro charged $500 a 4x6 for snapshot quality.
But then again I've been shooting seriously since about 1975.