If you expect to earn nearly all your miles from charging to a credit card at 1 mi/$, you might consider Visa/MC cards that accumulate miles in their own programs. I think MNBC has such a program, as well as others - there may be more on this in the Visa/MC threades. You then use those miles to get tickets directly rather than transfering them to an airline.

Benefits: You need fewer miles for a given trip.

Drawbacks: Limit on the $ cost of award tickets, not usually a problem with vacations. Cannot combine miles with miles from other sources such as flights or hotel stays, only a problem if you expect a significant fraction of your miles to come from them.