Nikon D7000 is the way to go.
I had same illusion one year before that there isn't much difference between Canon 550D and Canon 60D/7D as all have same sensors.
BUT .... while having same sensors, the performance and focusing capabilities of other two are much better with some other important features which now i feel i should have in my cam after using Canon 550D for one year.
However, for a person who is new to photography, these differences will not matter as u can only feel and notice the performance and other differences when u have some experience and know that what u need and what u miss in different situations.
Comparison
The biggest difference would be focus points:
D7000 is 39 with 9 cross type and D5100 is 11 with 1 cross type. Cross type points are more sensitive to focusing mechanism and give much better chance and more options to focus. Non-cross types either follow horizontal line for contrast detection or vertical line but cross types run on both vertical and horizontal lines to detect contrast for focus and give u much higher chances of achieving better focus. And u also have 30 more horizontal or vertical focus points in D7000 as compared to 10 of D5100.
Focus motor for auto focus is another nikon specific plus for D7000 which allows to focus with cheaper nikon lenses.
Battery life is double. I really miss this as Canon 550D is not that good in battery performance.
FPS rate is only important if u want to shoot fast moving subjects like sports, races, birds etc. otherwise it won't be important.
The viewfinder is bigger, more clear and brighter of D7000 as compared to D5100 which comes in handy.
Couple of other differences are 1/8000 of shutter speed in D7000 as compared to 1/4000 of D5100 which really freezes water shots if u like to shoot water and 2 memory card slots in D7000 as compared to one of D5100.
Also, D7000 is weather sealed.
But D5100 is cheaper, lighter and smaller and u can hardly tell the difference in shots unless u do pixel peep or know already where to look for difference
But that is true for many other canon nikon wars :).
Also D5100 has fully articulated LCD.