Although it does have an annual fee of $45, for travelling, I'm a fan of the SPG Am Ex (Starwood hotels including Sheraton and Westin chain). I initially signed up because you can swap 20,000 SPG points for 25,000 miles on almost any airline frequent flier program. You can also use points to book airline tickets through SPG that avoid the blackout dates/restrictions applied to frequent flier points.
However, we found we use it mostly for hotel stays. Through cable bill, cellphone, gas, groceries, school tuition, we've churned $30,000+ annually through it, which gives us "gold" level status. The "gold" status gives you a preferred room, or often a room upgrade at Sheraton/Westin properties. We've used our points for stays at Niagara Falls for New Years, Maui, Kona, a week in Orlando, week in DC, weekend trips to Cincinnati, Detroit, and Anaheim. They upgraded our Maui room to some enormous ocean front room so big it had a doorbell. Our New Years Eve room in Niagara was upgraded to a view of the American Falls and Fireworks show. It's nice because all taxes are included with the stay, so you can walk in/out without having to pay any charges for your stay.
Also, the conversion rate seems greater when staying at their properties. Our hotel rooms in Maui, Kona and Niagara Falls were at least $400/night, but we used 10,000 points, so over a 4% rate of return versus maybe a 1% ($100) return on cashback plans. Even the 3,000-4000 point hotels are probably around 2-3% rate of return based on $80-120/night rates.
https://www201.americanexpress.com/cards/Applyfservlet?csi=6/15015/b/57
Another rewards card we just enrolled for is the British Airways Chase VISA. I don't see it being a regular card for us and we'll probably cancel after we use the miles because it is $75/year, but they're giving 100,000 miles on British Airway's frequent flier program when you sign up for the card and spend $2000 on the card in first 3 months. Enough for two roundtrip tickets to Europe or 4 roundtrip tickets in lower 48. Signed my wife up for one card and myself up for a separate card, hoping for 200,000 miles.
http://www.mychasecreditcards.com/britishairways/hp_1