I've had the AS signature Card for a couple years now and put it to plenty of good use. But in talking to other people (and reading through this thread) it seems like many others are getting a ton of value out of having other cards as well, at least to supplement their AS card.

I've been looking online and found a lot of popular names coming up - Chase Sapphire, Starwood Preferred, Citi Prestige, etc - but it's kind of unclear how good any of them are for AS travelers since many are linked up with non-AS airline alliances.

So I thought I'd point the question to you all: as common AS and AS-partner flyers, which cards do you use and why?