I like candids, but they're harder to get. The moment people see the camera, they either freeze up, or they pose, but with a candid, you're able to capture the true feeling of the moment.
For example, one of my favorite pictures of my daughter is
a candid I took on Easter in 2005, showing my Ex that yes, the camera did work, and was able to take good pictures (please ignore the really messy background). She was distracted and didn't notice me taking the picture - which worked beautifully.
Later that same year, a friend and I took my daughter to one of the parks here in Austin, because I wanted some photos to be able to send to family. Him with his spiffy Olympus E-300, me with my little Kodak DC4800 (at the time). 90% of the photos we ended up getting were posed. She knew we were there, knew we had the cameras, so she posed (or downright refused to cooperate). But with both of us there with cameras, we were able to get some very candid shots, that, at least IMO, turned out better than the posed shots.