Congrats on the pending arrival of your fruit! Cool to hear you're already thinking of getting the babe right into rovering, but I would definitely follow the above advice concerning taking a newb on the trails.
Britax is consistently ranked at the top or near it. There are several models available and, other than the Graco Snug-ride we used for our first child when he was a freshy, Britax is all we use. Specifically, we've had good luck with the Roundabout, Marathon and Frontier. Pretty sure we've used another,too, but can't recall the name. I, too, have heard good things about Recaro, but I believe their seats perform better for toddlers and up.
With respect to your D1, your child will, of course, sit rear-facing. My wife and I had a D1 when our first was born. We had to put him in the middle of the rear seat because the car seat did not fit behind either of ours - we're fairly tall. When the second child came, the D1 went by the way side, simply not enough room.
I completely agree with keeping your kids in car seats as long as possible. We have/do, despite the grumblings from the older two. Is it better to hear regular complaints or have empty seats behind you?
Best of luck in the coming months!
