Okay my first response would be (not in order) A child carrier(front for infant and back for slightly older) It is so much easier than the stoller in crowded places and if the child doesn't like being put down, you can move around the house with arms free.

A swing and/or bouncer my prone to ear infection son spent many a late night hour happy in his swing while I dosed next to him on the couch. (Okay I had to wake up a bit to restart it, but he was safe and content)

A lullabye CD that you love (cause you'll hear it 1000+ times. Use the same one when you put them to bed over and over and they will associate it with sleep even when you aren't there. Of course making your own would be doubly wonderful...