My favorite rifle (that I personally own) is my Bushmaster AR-15. Say whatever you want about the AR. I know there are plenty of haters out there, but the ability to put rapid and accurate shots wherever I want, makes this my favorite rifle. It has also been 100% reliable. My AK-47 is really fun too but I gotta give the edge to the AR. The remainder of my rifles are fun as well but AR and AK are the top 2.
As far as pistols go, I have a much harder time deciding because I shoot them all a lot and they all fill different niches.