If you're specifically looking for motion-based play, you really have no choice but to go with the Wii. Third party developers have largely ignored the possibilities of these control schemes - shovelware aside - so you have to rely on first party titles. Microsoft has mostly produced their own shovelware for Kinect, and Sony has limited the degree they implement motion control even in their first-party titles. Nintendo focused on motion control and is pretty much the only company that's demonstrated facility with them.
If you're interested in a console and the motion controls are just an extra, the PS3 and 360 both have deeper libraries of (good) games at this point. Most of those games are cross-platform, so you're mostly choosing between a small number of exclusives. For my purposes, the PS3 library is the more appealing of the two - Valkyria Chronicles, Metal Gear Solid 4, the Uncharted series, God of War 3, Dark Souls and Demon's Souls, for example, as opposed to Fable 2 and 3, Halo 3 and 4, and the Gears series.
With that said, Kinect is the most impressive tech. The PS Move and the Wiimote are effectively the same, despite working in different ways, whereas the Kinect is genuinely something new, and something really neat. Unfortunately, the Kinect is kind of buggy in terms of games with any degree of depth. It's not yet clear if the technology just isn't there yet, or if the ideas about how to use it aren't there yet.
The PS Move, sadly, just isn't used that much despite being the best of the three in terms of actual gameplay. It's very precise and does everything a fully-upgraded Wiimote does, it's been well implemented when it is used, but there's very little to do with it.
