In my experience, getting cats neutered is one of the biggest behaviour changers. There are some breeds that are friendlier than others, and other than Ragdolls, Russian Blues are generally extremely friendly. I have two, a male and a female, and they're both wonderful. They don't mind large crowds, even if it's people they don't know. They both love to sit on my lap, and will often sit on me at the same time, one on each leg.
As for male vs female, I haven't noticed any difference in mine, but word on the grapevine is that neutered males are the friendliest.