[quote name='Derfel']Dance Central, Kinect Sports and (especially) Child of Eden are generally the most well-regarded of the Kinect titles (CoE doesn't require it, though). If you have younger children, they will probably like Kinectimals (which just had a new version announced that includes bears). There are also some fitness games that are supposed to be good, I hear.[/QUOTE]
Haven't played Child of Eden, but I agree with the other 2. Kinectimals is surprisingly fun. Has Halo easter eggs. Kinect Adventures is pretty good too (comes with kinect). Just doesn't have a wide variety of games.
Kinect Game Labs is loaded with a bunch of fun stuff and most of it is free. Avatar Kinect (part of Fun Labs) just came out. Only tested it once, but it has a ton of potential.