What do you want to do with it video terms? If you don't plan to use the video then get the D3100, it's what I use. You won't need anything more for a while.
Both are very similar, take some time with each and see how the button layout fits for you.
Dont go for the higher price tag because you think your pictures will be any better, you would be very wrong if you believe that. Skill and knowledge is everything in this hobby.
This was taken with a d3100 and a 35mm 1.8g
This post was edited by pimpdawg on Feb 4 2013 03:20pm