DHR:
I LOVE a man in a nice (dark, well tailored) suit.
Of course I love a man out of one, too. 
My personal opinions follow-
(I’m the one that my college guy friends would take with them to buy their interview/business suit, so I guess they at least thought I knew a thing or two.)
Three piece suit – passé, too ‘80’s
Watch chain – poseur
Cuff links – nice touch, in the right environment/occasion/profession (e.g. banking) or for euros/latins
Tie pin – ick, too salesman in a polyester sportscoat
Tie bar – a bit past it, but not a horror, ditto for collar pins/bars
Suspenders – Those “statement” suspenders are over for the most part, thank god, but a nice pair of braces on a dark, English/traditional-cut suit can be niiice.
Bow tie – well only if you’re going for the whole English professor/eccentric/dweeb look. And it then becomes part of the man’s persona.
Suit jacket with only one button – fine.
Suit jacket with three buttons or more – 3=fine. >3 = fine on younger men and/or in the more “creative” professions, a bit too “fashion” for the older or more conservative ones.
A fedora – Give me a break, unless it’s Halloween or swing dancing. Or you’re Tom Wolfe.
Mostly I’ve worked (and dressed) in somewhat conservative large corporations. Now I have my own company and we’re business casual (no jeans, etc.) unless meeting with clients (suits).
Currently I wear a suit a couple times a month, for client meetings or presentations. When I was in big corporate America, I wore them a couple times a week, esp. for exec presentations. Rest of the time it’s women’s business casual: skirt or trousers and a shirt, blouse, sweater or sweater set. It tool a while to get the “hang” of this.
Thankfully the color and style range available (and acceptable) in women’s suits has expanded greatly in the last 8-10 years. And the office in general has definitely gotten more casual on average.
As a business woman, I’ve almost never worn dresses for business (day). They’ve always been viewed as too “secretarial” for the executive women. (Go easy on me, I’m not saying I agree with this, just that it’s the common perception in the more traditional environments where I’ve worked.)
For an interview, (as –er or –ee) I still like a suit. Shows you care, to my mind. Go ahead call me stuffy. I don’t care.
As for outside of work (what’s that?)-
It’s also more conservative/formal in the east vs. the west, especially in the evening. In Denver, a jacket was rarely required/expected in a restaurant. Here in NJ and other eastern metro areas, it’s more expected, esp. in DC – the MOST conservative-dressing town I know. Although there was that time when I was living in Baltimore and gave a cocktail party – sent out printed invitations and everything – and people came in everything from suits to gym shorts. Hey, if I’m going to this much trouble to throw a nice party, at least you can get dressed and look nice!
The most formal affair I ever attended was a Ball where the dress was “Decorations”. That means white tie, and if you’ve got medals, wear ‘em.