A FEW CHECK POINTS WHILE BUYING A CAM :-

1> Resolution.
2> Zoom (more the optical zoom better is the camera , optical preferred over digital zoom).
3> Image quality i.e High pixel size.
4> Red-Eye-Reduction-Flash.
5> High ISO support (50,100,.......3200).
6> Aperture speed setting (for low light fast lens is required).
7> USB 2 support.
8> Built in microphone.
9> Weather protection.
10> D-lighting.
11> large LCD screen.
12> Lens shift vibration reduction.
13> Size.