DD1 (9) - no seat or a LBB (either Literider or bottom of Monterey) depending on the car. 70lbs and close to (if not over) 60 inches.
DD2 (6) - Britax Parkway SGL in all cars she rides in. Not sure on her stats, probably between 45-55 lbs and no clue on height.
DS (18 months) - RF in a Marathon 70. I need to check his height next time he's in the car though and make sure he's not too tall for RF. He's 32lbs, so he's got a little time on the weight. But he's also 36 inches tall and is longer in the torso.