Character Descriptions: How Much of Their Appearance Do You Want to See?

I saw a reader poll on the "Romance Writers" Facebook group I belong to, which asks how much detail is enough for you to picture fictional characters while reading: every facial feature and hairstyle, hand gestures, body language, voice, clothes, race/ethnicity, or very little, to leave it up to your imagination?

Here's the poll:

How important is it to know exactly what the characters you're reading about look like?

a) I want to feel that I know the character, but only distinctive features, voice/scars/height/race.
b) Very important. I want to be able to have a fixed picture in my mind.
c) I want to know what they wear, down to their shoes and make-up, otherwise I'll keep flicking back looking for a description.
d) Just a mention of race/height/hair/eye color once in the story is enough.

I write historical novels about real people, but if there are no existing portraits of them, I try to find a real person I can imagine that character as--for instance, in my biographical novel Sharing Hamilton, his mistress Maria's husband James has no existing portraits. He was Scottish, and I pictured him as the Scottish comedian Billy Connolly. It made it SO much easier to write about him; he came alive for me.

Billy Connolly (James Reynolds in my book SHARING HAMILTON) 

Any All My Children fans still out there? Anyone remember actor Michael Nouri, who played "Mountain Man" Caleb, whose house Erica Kane's plane crashed into? (she walked away without breaking a nail, of course!)

In my biographical novel Eliza Jumel Burr, Vice Queen of the United States, I pictured her first husband Stephen Jumel as Michael. After that, he also came alive!

Michael Nouri (Stephen Jumel in my book ELIZA JUMEL BURR, VICE QUEEN OF THE UNITED STATES)

Also from All My Children, I pictured the actor Vincent Irizarry as my hero Fausto in my vampire romance A BLOODY GOOD CRUISE.

So, picturing the characters is most important to me. Also, good dialogue is important; every character should have a distinctive voice. But don't go overboard on the dialect--I once read a book with a Scottish hero, and his dialect was so distracting, I had to translate as I went along.

Comments anyone?