I routinely pay about $10k per month in credit card charges for my business... and as I was booking some airline tickets I started wondering if maybe there is a credit card I should be using that will give me free flights or something.

(I currently just use the credit card that is associated with my bank. There is no annual fee or anything, but there are also no "rewards". I pay off the balance in full every month, so interest rate is not important.)

What "rewards" card do you use? Do you think it's worth it?

Air miles etc. There are loads. I get junk through my door about it. Watch adverts too!

I don't actually live in the US any more, so I was hoping for some actual recommendations. :)