I definitely still pronounce words the American way, but more-or-less, I'll use the British vocabulary* (lift, aerial, crisps, and so on). I don't think I could even say "water" the way DH says it without sounding weird, and don't get me started on buoy. I have; however, sped up my speaking tempo - to the point where when I'm visiting the USA, it feels like everyone is speaking slowly.
* Except minus in relation to temperature. It's negative [number] gosh darn it.
The thing that gets my colleagues every time is how I say merry, marry, and Mary. I'm not sure if it's a widespread American thing or a regional American thing, but I pronounce those three words exactly the same.