I took two years off between high school and college (I ended up with 2 Bachelors and a Masters), but I don't think that has helped me in the least in terms of employability.
I'm not convinced a gap year is meant to increase your employability, rather to help reset your mind after high school. It helps you find out who you are, what you like and dislike, and helps determine if you really want to get that communications degree or if maybe a finance degree is more what you're looking for.
That's funny. Even after two years off, 2 bachelors, and a masters I still didn't know what I wanted to do! I have a bachelors in Ancient Near Eastern Studies, a second bachelors in Linguistics, and a masters in Educational Psychology. But I work as a web developer for the sales team of a large company. I was actually about four years out of college before I started getting a feel for what I might want to do with my life (i.e., about 12 years post high school). I'm very happy with what I do now so it all worked out.