ach & wfm:

If you don't mind collecting AA miles, Citi's World MC has no pre-set spending limit. That doesn't mean you can totally disregard the credit limit, but they will let you go over it a bit without dinging you for the fee. On one occassion where I was going over too far for Citi (and before I learned how to increase the limits - which I learned here on FT), they declined the charge - without hitting me with the OTCL fee. I've learned to call ahead of time if I need to go over the limit. In the past few months, I've been able to go ~$20K over - but I clear it with them first. I also pay the balance in full every month, which makes Citi more comfortable in letting me exceed my limit.

Also, it's been very easy to get my spending limit and credit limit raised, and unlike with Amex, I didn't have to wait six months to do it - you just send them proof of "ability to pay" - assets or income. If you do go with this card, know that there's a big difference between the spending limit and credit limit. Citi can adjust your spending limit up or down without telling you. And the people that grant spending limit increases don't talk to the credit limit people. Go for a credit increase first, then work on increasing your spending limit on top of that - if you need the room.