I just got a Nikon D3100 with a 18-55 lens and a 55-200 lens for 800. The shop I went to said Canon guys will recommend Canon and Nikon guys will recommend Nikon, but both are very good cameras. I went with Nikon because the deal I got on the second lens and Canon wasn't offering it.
The 3100 is similar to the 5100 big differences are the Mega pixels and the flip-out screen (I couldn't care less for this feature). If you get one from a shop see if they have a class to help you explore the features. I plan on going to one once i get back to St. Louis.