Often people think that the SPG card is only good for Starwood guests, and that's simply not true. The SPG is a very good primary card regardless of what hotel chain you stay at. With the points you get, you can either spend them on SPG properties using cash+points which is a very good deal, or get the flexibility of a ton of airline partners, at a 1:1.25 ratio.

Priority Club is also a good hotel chain to stay at, IC RA is unbeatable as a top tier program (though they don't honour elite benefits for award stays), and their PointsBreaks list is great for a bargain (mostly HI's but a couple of CP's and the odd IC or two)