The 7D is a ridiculously complicated camera.....I've spent hours playing with settings and getting it set up just how I like....there's some useful videos here -
http://www.usa.canon.com/dlc/controller ... eTypeID=48As Doug says, the grain will be a result of high ISO, although I've found that the 7 does deal with high ISOs admirably well, especially if your post processing is up to scratch

I really wouldn't advise using that camera on full auto....if you do, then you might as well have bought a point and shoot. Learn the basics of photography - like how aperture and shutter speed are linked and what changing them does. This will help you decide on what settings to use for a particular shot depending on light available and required depth of field etc. Also put a lot of effort into the Processing....it's the equivalent of a darkroom for 35mm photography, but so much more can be done in photoshop. However, the basics are the same....adjusting curves, rotating, cropping etc. Almost all photos will also need sharpening (loads of tutorials online as to how to do it, but I would experiment to find a method that suits you).
As a rough idea, if I'm editing a photo properly, I can take up to a couple of hours on one image....this will end up with having about 6 layers and layer masks that allow me to edit the back and foreground seperately...these techniques would be explained in a decent book on post processing digital images.
Good luck with the camera, and have fun

.mic