It's the Britax Advocate CS in Onyx. Even though we made great use of the versatility of our current infant seat because it was compatible with our stroller system, if we had known about the Advocate we could have gotten away with buying just one car seat, instead of two.
The Advocate's safety features are impressive, and it allows kids to ride rear facing until they weigh 35 pounds--which is important to me. We were a little surprised when we found out it cost 400 dollars, but can you put a price on safety? I don't think so.