The Capital One Venture Rewards card is Capital One's flagship travel credit card. Indeed, it was named Money magazine’s “Best Rewards Card” for road warriors seeking free flights. Not to mention, the miles won’t expire, and there is no limit on how many can be earned.
This is a simple, no-frills, fast earning travel card. You earn two miles for every dollar you spend, and then calculating how much money towards travel purchases that backs out to is easy - you divide the number of miles you have by 100. Let's say you have 21,700 miles, that equals $217 towards a flight, hotel room, or a number of other things in their rewards categories.
Basically, you earn 2% on the dollar on all purchases to put towards Capital One's rewards category. No restrictions. No expiration. Just Rewards for miles. There is an annual fee of $59 after this introductory first year, so make sure you are going to be using the card frequently enough in order to compensate for this added cost.