OP: Welcome to FT! it all depends on which miles programs you will be focusing on. Yes you can sign up as many cards as you like, but coming down to where to put your spending, the most popular cards with flexibility are Amex SPG, Amex PR Gold (even with several devaluations this year), and Sapphire Preferred. Of course, if you are loyal to a certain FF program, their affiliate cards MAY be useful as well.
Check out my website for my review on SPG vs. MR vs. UR to gain some basic idea.
Originally Posted by
kiyotaka
Dose dining in foreign country count? Like mexico, Europe?
As long as the merchants are coded as restaurants. Plus Sapphire Preferred has 0 forex fees.