My great-grandmother made me promise never to marry a Catholic.
She calls marriages between two people who aren't exactly the same religion--even, say, a Baptist and a Methodist--"mixed marriages."
Myself, I am no religion. I was never baptized, and I never attended church regularly for any length of time. I have pretty, er, "liberal" views about religion, so really, a guy's religion is a non-issue for me unless he's super-religious and super into his church. (Once I dated a guy in seminary, and boy, was
that a fiasco!)