SD has higher read/write speeds than Memory Stick and has higher capacities than the original Memory Stick. Memory Stick Pro, OTOH, goes up to 1 GB. Neither will affect picture quality at all--that all goes to the camera. so I'd be more concerned about the camera maker and its features than the memory format it uses unless you already ahve a but or SD cards or something. Sony makes great digital cameras, and so does Canon. Pretty much any digital camera you get from one of the big manufacturers will be pretty good--Sony, Canon, Pentax, Nikon, Olympus and HP all makes fine digital cameras. Some are better than others, but there is more disparity between individual models than between manufacturers in general. Just stay away from the new Gateway cameras and anything that seems too good to be true (ie 4 MP for $150 might take big 4 MP pics, but you'll have poor color fidelity and artifact-ridden pics). What kind of features and picture quality are you looking for?
BTW, i believe we're talking about digital still cameras here, not MiniDV, manitou.