Honestly, I have some good guilds in mind that I COULD suggest, but I'm not going to, simply because my answers will obviously be the ones that I'm a part of. Your best option would be to browse the forums and look at the guilds both mentioned above and listed throughout POF. Look at their threads, taking into consideration their rules, members, activity, etc., and see which guild suits
you best. And if you see one that you think fulfills your needs, congrats!
I wish you the best of luck on your guild hunt!