Sarah.
I've been talking to Claire about this a bit and I'm wondering why the hell Ruby wants Sam so much if she isn't in love with him. Whatever her motive (maybe she just hates Faith) can demons do mind control? Do we know much about Ruby's powers? That...worries me.
You aren't evil at aaaall. Sam better not mess with you. I think he's smarter than that.
Bottom line: It's easy to extend exceptions to friends that you know, but it's not just the friends we know who deserve that brand of kindness.