I have the Citi Elite Rewards. I don't know if I'd get it again. The up side was that when I got it, if you spent $300 within the first 3 months (or something like that) they gave you 20,000 bonus points. Combined with some of my other purchases, that was enough to pay for my round trip flight from NJ to Miami to go on a cruise we had planned. They have deals for double/triple/etc. points for their preferred vendors (which change every couple of days/weeks), but there's a $75 annual fee which is annoying. Also, you can choose pretty much anything as your 'reward'. I do travel, but I know you can choose cash vouchers, or shop at their online store that has everything, donate to charity, etc.
I just recently got the Delta AMEX Gold Rewards Card because I fly Delta a lot so the points add up. I got the card in early Feb and with the bonus points and flight points so far I have 50,000 points. I'm saving them up to use for my flight to France in the Fall. No membership fee for the first year, $95 after that, and I just love how quickly the points add up from flights. But, being that it's AMEX, not everywhere accepts it, so sometimes I have to use my MC anyway.
If there's an airline you normally use, I would probably check into their specific airline card because the benefits are usually really good, especially if you're planning on using it for travel anyway. I think the more generic rewards cards are a little stingy with the points because they aren't getting the money back from them, whereas the airlines are.
Check these out:
Airline Credit Cards & Frequent Flyer Miles - CreditCards.com
Frequent Flyer Credit Cards - Best Airline Credit Card Offers - CreditCardGuide.com