DD's seat (rear facing) was behind the passenger seat. DH drives the car more than me, and therefore needs the extra leg room so we couldn't put it behind the drivers seat.

DS was moved to behind the driver's seat. Then we went to a BB meet up and picked up snugglybean, so we moved DS to the middle seat. The kids liked sitting together so much we just left them there. Now we have changed it a little (no reason why, just its the way DH put them in for some reason) DS is behind the passenger seat, and he likes to have his window open so this works well - and DD is in the middle. I like them close together (even though they fight and pinch each other sometimes) because they also entertain each other, and he can give her biscuits and stuff or a drink if I hand it to him (he's easier for me to reach) plus they also hold hands (awwww)

When this new bub comes, I'll have three seats along the back seat, so the plan is for DS to go in the middle because he can climb into his own seat, so I don't need to lift him in there. DD will go behind the drivers seat (forward facing) and bubs will go behind passenger seat.