I've found the baby intercom (Tomy Walkabout 2000)very handy although I can't find the downstairs one at the moment, I've started to turn out cupboards in the hope it'll turn up.
Britax car seat (the polystyrene one) suitable from 9 months upwards although I found it only useful from 18 months up as they both fell out the side of the seat belt when they went sleep in the car.