What do you wear to formal occasions?
Mine:
Polo shirt
Either black jeans or slacks
My belt with the civil war style "U.S." belt buckle
Dress socks
Shiny black loafers
I'll probably buy a real suit or something if I ever go some where fancy, because so far the most high class place ive been was to see Spamalot the musical.
Although it isn't by definition "formal," for nicer occasions I'll sometimes wear my mid-grey two-button suit from Land's End. Church, certain functions, and weddings and funerals should any arise (I would hope not the latter).
Usually, I wear jeans or khakis/chinos with dress shirts or polo shirts, sometimes flannel shirts or safari shirts too. Shoes are almost always leather, whether casual or more dressy.
What you have listed is a pretty good solid idea, but I would avoid wearing just black jeans if I could have dress slacks or dark colored khakis/chinos (same thing really) at hand. Dress socks are always a better idea than regular white socks for nicer occasions.
Without trying to sound like a jerk, does anybody else like fedora hats? I wear (but not all the time) the wider 1940s style fur felt ones. At least one of my collection is actually vintage too, from the late '40s. I'm into retro stuff from around the time of WWII though.... I even own a G-1 flight jacket.