re: monitor
We're really happy with our video one (Motorola of some sort), but we honestly didn't use it that much until a few months in. For the first three months she slept in the rock n play in our room, and frequently either napped in that, on us, in the pack n play, etc.
And at this point we actually don't use the monitor at night once we're upstairs and in bed (we can hear her fine from our room). What we do use the monitor for us during naps and then between when she goes to bed (7ish) and when we go to bed (10-11ish). As others have said, it can help when you hear cries/noise/movement to be able to check and see if she's really awake and wanting to get up vs just moving around and re-settling or something.
All that said, we do have a 3 bedroom, 2-story house with a basement and yard. It's not huge (i.e. we could probably still hear her cries ok from her room to our living room), but it is helpful if we're in the basement or out doing yard work or something. We also discovered the signal held from our ocean front beach house down to the beach when we were on vacation, which was pretty sweet.