I would choose cards that have unlimited points earning potential. My ranking opinions are below

High Fee/High Benefits/Unlimited Points:

1. AMEX Centurion - Broadest Airline and Hotel Benefits. High reward rate.
2*. Citi Chairman - High reward rate. HH Gold Status. Priority Pass airline club access. Not available right now.
3*. AMEX Platinum - Normal reward rate. SPG Gold Status. DL/CO/NW airline club access.
4. Carte Blanche - Broadest reward program. Normal reward rate. Benefits do not appear as strong as 1-3.


Moderate Fee/Moderate Benefits/Unlimited Points:

1*. Merrill+ - No Fee. Normal reward rate. AA status match with $20k spend. AA or DL club membership with $50k spend.
2*. AMEX HH - High reward rate. Automatic silver status. Gold status with $20k spend.
3. AMEX SPG - Gold status with $20-30k spend (check the website). 125% point earnings rate when you consider point transfer bonuses.
4. AMEX DL Platinum - High earning rate on select spending categories. Up to 20,000 qualifying miles per year. This will almost guarantee status.
5*. Diners Club - Broadest reward program. Normal reward rate. Primary rental car insurance.

If it is high rate of rewards that you want most. Pick from AMEX Centurion, Citi Chairman, and AMEX SPG. If you want certain status or benefits, pick from the other cards above. If AA is your favorite airline. You should consider AMEX SPG (highest reward rate), Diners or Carte Blanche. They are the only ones that transfer (other than Citi AA MC).

I chose the cards above marked by (*) because:

a. I live near a DL hub. I travel 90% on DL. Citi Chairman and AMEX Platinum give me access to all DL clubs and some other airline clubs.
b. Citi Chairman has a high rewards rate (which I use for gift cards since I have enough airline and hotel points). (The rate is the highest in my opinion among all of these cards. I think that Anaggie will agree.)
c. AMEX HH has an awesome reward rate for Hilton stays. I use Hilton 100 nights a year.
d. Diners Club gives me primary rental car insurance
e. Merrill+ gives me status matching on AA.

I only spend on Citi Chairman, AMEX HH, and Merrill+. The other cards are for benefits only.