ANY dslr will be good for taking action shots, its not really the body which will enable really good action shots, its more to do with the lens you are using.
Get a decent zoom lens, something between the 50 - 300mm range, with image stablisation if you can afford it.
The 50mm prime is all very well, and its fast wide open but you'll get a very narrow DOF so it wont be good for action shots IMO. Narrow the apeture and its not so fast. Youre also totally restricted in focal length which wont be long enough, I can guarantee, as when I take action shots of my dog I need to use my 55-250 when he's running about. It'll be ok for portraits though.
What sort of action shots are we talking about?