I've basically played them all and love it
Generally, I really enjoy games where I get to climb around stuff, so I'm really enjoying inFamous at the moment mostly just whizzing around
AC II is obviously still the best game of the whole series and one of my favourite games of all time. I enjoyed AC IV, but not necessarily as an AC game, but as a game in general. The cities just weren't that interesting and I feel I wouldn't have liked it so much if it had more next-gen competition.
I will be buying AC Unity and possibly the current gen game too. I really really really do love AC and I even love the modern day conspiracy stuff!