I did a wonderful, funded two year MA before applying on, and found that it was hugely beneficial. When applying to PhD's, I gave particular attention to those programs that would allow me advanced standing (programs that take 3-4 more years beyond the MA, typically, rather than 5-6 years regardless of previous graduate experience.) After all that time invested, I needed a PhD program where I could be in dissertation phase after two years.
In other words: I think a terminal MA is a wonderful, useful, very advantageous thing. But after, find a program that will consider those years in a serious way toward your graduate training. Not a program that will ask you to start over on a possibly 7 year stint.