I have had both aggressive and really friendly RIR hens. I have had both white and brown leghorns; both types were very flighty, but not aggressive. Of all the breeds I've been through, my friendliest chickens to date have been RIR, Easter Egger, Rhode Island White, and I had a really nice Cuckoo Marans. Most of the rest have been calm and easy to be around, but not necessarily "friendly".
Oh, BTW- I have been through a number of roosters as well. A cochin was the nicest by far. I currently have a Lavender Orpington that is a pretty friendly guy, but who isn't against chasing a stranger out of the yard. Meanest roosters that I have ever seen were both bantams (mille fleur d'uccle and a golden sebright). I think they must have a nasty case of Napoleon complex.