A note from Sarah Page: Scott originally wrote this post years ago, but it is still very much valid and important today. 

Once a month we update a list of what, are in our opinion, the best travel credit cards on the market. We also update a similar list, but for small business credit cards, monthly. How I rank them is largely defined by their sign up bonuses. So the next logical question would be, how do I value those sign up bonuses?

There are two equally valid ways to value a credit card sign up bonus.

A couple weeks ago, I booked a one-way Delta One flight between Atlanta and Buenos Aires for 45,000 Virgin Atlantic Flying Club miles (and just $5.60 in taxes). I was pretty dang excited about the ability to do this, as it was my previous assumption that Flying Club awards flying partner airlines--at least Delta specifically--needed to be booked roundtrip. That is not the case.