Where are your expected destinations?
And what does NAM mean?*
*edit: disregard. I think question 2 just answered question 1. D'oh.
I've had great success out of YVR with UA, which will help if you do some domestic flying with AC. Others claim DL is an excellent choice. I suppose it does depend upon which cities you expect to travel most frequently. I suggest DL, mainly to prevent another UA Platinum from competing for my own upgrades.