The one thing that I can think of that's missing from every Mac -- current and present -- is front-accessible USB and Firewire ports. While you can always add hubs for these ports and place them within reach, it'd be great to have ports on the front so that if you don't have a hub you don't have to reach around the back of the machine to hook up a USB key or a Firewire camcorder or whatever. If I could get hold of the ear of someone at Apple who could make decisions on product features, that would be my contribution.
How about you? What would you add or change to the current crop of Macs to make them better or more complete?
I don't know if anyone from Apple watches AppleFritter, but maybe they are!