I remember watching in awe as images from the encounter of Voyager 2 with Neptune were broadcast on television in 1989. I was in college, and deeply enamored of astronomy, so each of those rare pictures was like manna from heaven.
Now, of course, we live in the Future. I can go to one of NASA's many websites and download megabyte after megabyte of images from the two small robots which are crawling over the surface of Mars. The images uploaded to the site on February ninth are particularly interesting, as they include a picture of Rover Opportunity seen from space taken by the Mars Global Surveyor orbiter.
Ah, the twenty-first century...
Tho' I think my favorite image from the Mars rovers recently is this one. Opportunity emerged from the crater it landed in and caught an image of the parachute and backshell it used to land. I imagine there were some interesting emotions going through the JPL control room before they realized what this was.
A while back I said that only five spacecraft have successfully returned images from the Martian surface: the two Viking landers, the Pathfinder rover, and now Spirit and Opportunity. It turns out that this was not strictly true. If you continue to explore that site you can find all sorts of other rare planetary probe images, including these dramatic pictures of Mars and Phobos together and imagery from the Soviet Lunokhod 1 and 2 rovers, which traveled large distances across the lunar surface in the early '70s.