I never played COD until Black Ops, should I try the others?

My wife has played the others & says its not worth going back & buying them. I kinda wanna play them because the maps, weapons & perks are all different & even tho theyre older games, theyre new to me. But then I start to wonder when the next COD game will come out. Do youthink theyll have a new game ready for this christmas or not til the following?