American Express Membership Rewards - Amex or Airline Card?

I've had a Plat Amex for years and therfore, gave up my CO Pres Club Card in order to avoid duplicate card costs. I just signed up for a Starwood Amex and am womndering if I should re-instate a Pres Club Card and give up Plat Amex...the only reason I am asking is that I see the other great options like Cashback Plat card, Diners Club, and since Starwood has no annual fee, it seems a waste to keep Plat since I don't use the dopey benefits like restaurant reservations they have yet to ever get me in. I happen to be furious at Amex right now anyway, so perhpas any solution whereby you can recommend I switch I'd love it.

The Starwood Amex is free for the first year but every year after that is an annual fee.