I guess while you test-drive different examples (auto vs. man), see which one you would prefer to live with day in/ day out. The only model which doesn't give you a choice is the Nismo: u gotta have the manual.
The manual might take some practice to get good at driving it: when you get it perfect, it'll be a good feeling. An automatic is nice and smooth: you'll have a free hand while driving if you want to hold a drink or talk on the phone. I like both types of tranny; however, I chose an Auto :-).