generally speaking, on a windy day outdoors, machine-gun shooting can come in handy. especially if the model has long hair and/or is in motion. in a studio setting, machine-gun shooting is not quite so necessary, unless the model is in motion.
when one has full control over light and has experience with a given camera, then jpg can be great. when the exposure may be in question, and/or when one is shooting a dark object against a bright background, or vice versa, raw would be the better way to go. raw gives more flexibility in post-processing, so if it's an image you're going to want to photoshop a lot, go with raw! also, many say that ultimately raw can give sharper images, but that would depend on a lot!
the general trends are towards 1) less expensive hard drives 2) less expensive CF/SD cards, so the fact that both raw shooting and machine-gun shooting tend to take up a lot of space fast, is becoming less and less a factor. also, jpeg oft works better for machine-gun shooting as it allows for faster/more continuous shots--so if you're shooting a model with long hair on a windy day, continous/jpeg is probably your best bet for catching a usable photo.
long story short--shoot both jpegs and raw--shoot both machine-gun style and short bursts! see what works for you and your camera, as the raw vs. jpeg feel varies form camera to camera! keep the options open and use them creatively in the shoot, as needed.
and finally, play around with the video on your camera! i recently saw many people in a forum adamantly stating that they wanted canon and nikon to *remove* the video from their dslr cameras, and i don't think they were joking! last night i was reading a magazine and all the up-and-coming pros featured were talking about how they were using the canon 5d to shoot video too--i'll find the article and post some excerpts here. the bottom line--have fun playing around with the video!
rock on, have fun, & shoot it all! :) develop your own style. & remember it's not about the camera, nor you even, but the photograph.
Hero's Journey Entrepreneurship Principle #51: Play.