I worked with a girl once who absolutely refused to entertain the thought that she might ever be in a relationship with a person who was not Muslim. Upon asking her why, she had no response other than "I just wouldn't". It got me thinking something, though: I would never consider a relationship with someone so closed-minded.

I, raised Catholic, currently of no affiliation, have dated Catholic, Orthodox, Jewish and Christian (of varying shades) girls, and honestly I haven't had a problem. Of course, none of them took their religiousness very seriously, with the most committed attending Church every Sunday.

I think that at the root of your question, you should be looking at the intensity of someone's beliefs. A practicing by-the-letter type would not fly with me, probably because I'm too anti-organized religion. However, someone who is moderate in their beliefs and does not force them on others is fine by me, regardless of race or creed.