Let me tell you how and why I choose Nikon D5100.

     I was disappointed with my Sony hx-1 photo quality, the grains in the photo was unavoidable in all situations. Also the DOF was quite OK. I used Sony hx-1 more than a year.
     When I was feeling to move to DSLR but  all time i had a same thought "which one". Again its not a easy job as we are investing so much of money and buying any entry level DSLR is not at all right.  That has to be right one.
I refereed this site more for comparing cameras  [link].
I ended with selecting 2 major manufactures as I don't want to take any chance with other companies. you know these CANON and NIKON.

(Feature):- (For 5100 ) vs (For Canon)
Significantly lower noise at high ISO :- 1183 ISO vs 793 ISO

Much better image quality :-                    80 vs 65

Much better color depth :-                      23,5 bits vs 22,1 bits

Much more dynamic range:-                  13,6 EV vs 11,5 EV

Continuous video focus:-                     Yes vs No

Has in-camera HDR :-                     Yes vs No

Much less startup delay :-                     500 ms vs 1500 ms

Video autofocus :-                                      Contrast detection vs None

Longer battery life :-                     660 shots vs 440 shots

Larger sensor :-                               APS-C 23.6x15.6mm vs APS-C 22.3x14.9mm

Better boost ISO :-                               25,600 ISO vs 12,800 ISO

More focus points :-                        11 vs 9

Smaller :-                                        127x96x78 mm vs 133x99x79 mm

Slightly more lenses available :-                  169 lenses vs 162 lenses

Shoots slightly faster :-                         4 fps vs 3.7 fps

Slightly less shutter lag :-                     273 ms vs 283 ms