Locked down my sapphire bonus and almost have my Amex bonus.
Is there a no-brainier to pick up next for a big bonus? If not, I will just keep using the Sapphire for everything.
At first I didn't really appreciate how awesome the Sapphire is. It is close to making all other branded cards (eg a Delta card, American card, Marriott card) obsolete because of the double points on "travel." Add to that the flexibility of the UR points, and this thing is great (and the double points on dinning).
Apart from signup bonuses, you could make the argument that Sapphire is all you need. UR doesn't cover all airlines, and the Southwest conversion isn't as good IIRC, but man it's still very good.