I'm not sure what you mean by 'digital storage system'. I mean... all digital cameras/camcorders use digital memory, so you either put the memory card in a reader or you plug the camera into your computer to transfer files.
If you want HD Video... do you want 1080P or 720P? Very very few P&S cameras have 1080P, so that will push you to either mirrorless cameras or DSLR's.
If you want a pocket compact (which will all do 720P video): There's the Panasonic LX-5, and the Canon S95, or if you want more zoom, the Panasonic ZS5 or ZS7. With the ZS5/7, the aperture control on it is really a joke though.
Mirrorless cameras are more expensive, but they take better pictures. The Olympus E-PL1 is around $500 I think. There's also the Panasonic GF1. The new GF2 probably breaks your budget. All these cameras can take fisheye lenses, but I think they are *really* expensive.
For DSLR's, you're going to be looking at budget models. The Canon T2i probably takes the best video. The Nikon D3100 is decent. If you want a smaller DSLR, there's ones from Panasonic again... the G2. The Canon 7D is way over your set budget.
If you get a camera AND a camcorder, it might be more than $600 though, depending on what you get. HD Camcorders are kind of expensive.
Yeah ok... I'm a camera whore xD Interests: Photography. I said it and I mean it!