Which Camera would be better for video?

Sony Cyber-shot DSC-HX200V
Or
Nikon D5100 DSLR with 18-55mm VR Lens Kit?

For video HX200V is better as the main design of D5100 is for photos.
Also you can save some money for getting some extra lenses.
but if you want better photo quality then D5100 is better.

Nikon, the company backs up its product better than Sony.

The D5100 is in a completely different league to the Sony, which is nothing more than a compact on steroids. However without the necessary experience both cameras will look the same.

If you want high quality stills like a dSLR, but a better video shooter, go with a Sony dSLT like the A57, Canon and Nikon can't touch the video performance. That does not make the A57 the best camera, but better overall if video is important. If stills were more of a priority, then I would suggest the Pentax K 30 over the Nikon D5100. If the A57 is too much the A37 is pretty good too, but it loses a few features.

Http://keerok-photography.blogspot.com/2012/09/use-right-tool-for-right-job.html
http://www.bhphotovideo.com/...Camcorders

It depends what you want to do. Both will record full HD at 1080, but the Sony has a higher framerate than the Nikon.

For general purpose shooting the Sony is excellent, and it can be pushed quite hard into getting results normally only achieved with higher-end video cameras. I use the HX20V and I used the HX9V before that. I'd highly recommend the Sony range. Add a screw-in handle for the tripod mount, a hood loupe on the back and a magfilter ring on the front and it's an extremely capable and comfortable camera.

If you want the stills quality as well, go with the Nikon. But I personally don't rate any of the Nikon entry-level models (D3000, D3100, D5000, D5100, etc) as Nikon insist on missing out the focus motor in the camera body so you're restricted to a smaller range of lenses if you want to retain autofocus.

Whichever you decide, don't expect much from the onboard sound recording. Get an external sound recorder (eg the Zoom H1) and edit in the sound afterwards.