I recommend you think a bit more about the type of photography you'll be doing.
The D3200 is the highest resolution, which makes it a good choice for landscapes. It also has the Guide mode, which is good for explaining what all the functions do (though the Sony has something similar). I do worry that this is the one you'd be most likely to outgrow though as you get more experienced.
The Canons are good, solid all-rounders, whether you go for the fixed screen (550D), tilt screen (600D) or touch screen (650D). Canon has the biggest lens range too. Just.
If you're primarily into sports and action the Sony A65 is undoubtedly the best choice. And probably for video too, since you can use the viewfinder while filming. It has a great twilight mode for low light shooting, and as you said the Sweep Panorama mode is great if you like panoramic photos. But the lens range isn't as good as Canon's or Nikon's.
Very good summary Nigel. Was surprised by the additional longevity of the Sony but understand your logic, thanks!