optical zoom is 'REAL' zoom, i.e. a magnifying lens of some sort. digital zoom is blow-up zoom, where quality degradation is an issue. the higher the 'real' zoom the better. fake zoom is just like blowing up a negative or scanned picture, it can't add detail, it just spreads out what's there.
one of the frustrating things with our new camera (a Nikon, but this is true of most cameras that are reasonably priced) is the shutter speed. there's about 3 seconds between pushing the button and taking the picture. any movement of the camera or subject of the picture leads to blurry pictures. and it's hard to take any action shots (football games, etc.) when you've got that 3-second delay. the newer more expensive ones take the picture alot quicker, (like film), but they'll run you about a $1,000, easy. definitely something else to worry about.
memory cards can be pricy, but they're pretty interchangeable, you might be better off getting 2 or 3 64-meg cards, or just one big 512-meg card. we got one big card and have never needed to take it out of the camera. we just burn stuff to disc before getting prints made.