I've never been out with someone that I wasn't friendly with before. Every boyfriend i've had has been a good friend before, and it's always worked for me. Despite the fact that our relationships might not have worked out, I talk to every single one of them and consider them good friends.
I couldn't really imagine going out with someone that I didn't really know. Those guys knew me, I knew them therefore it was comfortable. I wouldn't feel comfortable around someone that I wasn't particularly friendly with.
Everyone is different though, you just have to do what feels right for you.