I guess this is a bit up to how you work as a person... I have a FB that's about a 5-6.. she's fun to hang with, has a good sense of humor, is fun to talk to... scratches my back and all the other stuff I miss when I'm not in a relationship.. and the sex is pretty good too.

I seriously feel that her presence is helping my game. Thanks to her, I honestly don't give a crap whether I get laid or not, most of the time sarging.. My goal is to improve my game, not getting as much booty as possible. I've never been that concerned about looks.. the flip side of it is that it's pretty easy for me to play around with an 8-9 (never met a 10 yet), 'cause in my head it's all "okey, so you have a good body.. one point for you... my shirt is nicer than yours, one point for me"
In my experience the mind set "I don't give a crap about your looks, and I'll only sleep with you if you can attract me enough sexually" works wonders, especially on the hotter girls who are used to guys falling all over them.
But anyways.. I have this FB relationship with her because I feel comfortable around her and like being with her. She might not be the greatest looker out there, but I enjoy her company.. and I would never be ashamed to say I know her or something (I know people with all kinds of looks.. all the way down to 2s or something). I'd say the rule is "never fuck somebody you're ashamed of". THAT would seriously hurt my game, but isn't something I would do.