worry re baby monitors, don't go super cheap (ie £20 or less) as in my experience, they often have poor quality sound or suffer with a lot of interferance. I'm a worrier too so I have one of the sensor mats that go underneath the mattress as go off if baby doesn't move for more than 10-20 seconds. With dd1 I'd wake up in a panic that something had happened as she hadn't woken up for a little while, that gave me peace of mind. Tommee tippee make a nice one of those. I'm really tempted to get one of the video ones as my hearing isn't good so if baby is in it's cot and I'm downstairs, I may not hear baby and would be nice to keep having a peek without going upstairs and disturbing baby. My friend had one of the motorola video ones and loved it, she sold it recently and I missed it by seconds, grrr.
Oh I've heard a lot of bad things about the BT monitor. Apparently it connects to an app but is supposed to be terrible. Not a recommendation obviously but one to not buy and waste your money on :)