AFAIK, Delta only partners (directly) with Amex, not Visa (or MC). If anyone knows of a Visa or MC card (especially with a good fat sign-up bonus) that directly earns DL miles, I'd like to hear about it.

As MDtR-Chicago suggests, the SPG Amex is a good way to go if Amex is OK for you. I've got the SPG Amex, and am looking for the next Amex card (SPG or other) to get for mrs. nwflyboy - she only has the Delta gold Amex.

Actually, I'm planning to close both our Delta Gold Amex cards (we each have one) in the next few weeks in advance of the annual fee coming due. The plan is to leave that fallow for 2 years, then try applying again, hoping to test the theory that one can indeed get the signup bonus a second time - if you're patient enough. We'll see.

In the mean time, I'm looking for the next Amex card to get to replace the Delta gold Amex for the wife - need at least one Amex (since that's all that Costco accepts).