I think that if my baby monitor had video when DD was born i would have drove myself crazy. Its bad enough hearing every little movement without checking the screen as well every two seconds. I think normal monitors are fine and the video ones are a bit of a waste of money.
I only spent £5 on mine from ebay and they are stiil working after nearly 4 years! The buzzing in the background is caused by electrical interference so dont put them too near lamps, tvs, stereos, u get the idea.