What to look for on a DSLR's LCD?

Question

I think the main features of a reflex's LCD are:

1. size
2. resolution (pixels/dots)
3. vari-angle or not

So how important is each one of them? Which one is the most important? What number of pixels is considered enough?

My concrete problem is choosing between Nikon D3100's and Nikon D5100's LCD. The first has 230,000 pixels and is fixed and the latter has 921,000 pixels and is vari-angle. It's one of the differences which makes the D5100 around 200€ more expensive. The question is: is it worth it?

Answer

Resolution first, given that size does not vary much lately (2.7-3"). That lets you check sharpness and focus better, particularly if you use Live-View.

Rotating or tilting (vary-angle) can be useful for somethings but is also a liability since it can break. No Pro cameras have such displays because they need to be tough first.

You forgot the viewing angle. If the display is rotating that does not matter so much, but otherwise having a good viewing angle helps with getting odd-angle shots using Live-View.

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