Does anybody know any good baby monitors?

I'm looking for a baby monitor to add to my baby registry and i'm not sure what to look for or which ones are good? I have a 3 year old but when I had her me and my husband shared a room with her and this time our girls will have their own room. I worry a lot and I know that if I don't get this I will probably end up sleeping with them. So if anybody knows of a good baby monitor I would love to know about it.