My vote would be for Visa Signature or World Mastercard, depending on the terms given by the issuer, even with a FICO of 850.
I didn't see much in the forums yet about World Mastercards (nor yet that supposedly pinnacle Saks 5th Ave World Elite card) in particular, but that Continental World from Chase is excellent if you fly that airline a lot, for sure. I just became a World holder of Chase's Freedom line (you can find the Platinum version on their website) at a fixed 10% purchase APR, no annual fee. Not the greatest APR, but as usual, APR is meaningless if one doesn't revolve balances. Chase gives what is called a "credit access line" (what I will label as CAL) rather then CL, and I'll learn next month if they report that to the bureaus as the CL. A CAL is simply the maximum one can revolve on a no pre-set spending limit card. I have prior MC and Visa platinum experience with Chase, which is probably one of the things required to be invited but, oh alas, I'm not part of the junior CEOs club earning $125k per annum (required for a number of Signature cards, according to places like Bankrate and Wikipedia). Maybe one day I'll qualify for a Signature card, but a World seemed a pretty good stepping stone at age 29.
As for the Amex Centurion card (or Black card), the thought of that $2500 annual fee curdles the milk sitting happily in my fridge. I suspect Centurion beats out Signature and World in the long run benefit-wise and how far it could up the angle of a less-than-humble nose
, but the majority of the CC-using world (outside of the US, UK, and Canada) doesn't take Amex, Discover, or Diner's. In recent travels, the #1 acceptable contender appeared to be Visa in South Africa (2005) and Mastercard in Ireland (2002).