(I have certainly used every word on that list, in published fiction. Except effulgent. Which I'm going to run right out and put in whatever I write next, because I am the imp of the perverse. But then, I have noticed that I talk a great deal about qualities of light, something to which the esteemed Ms. L. is apparently opposed.)
I must be the anti-Margo; I have lists of words that I am saving up for when I need them: sesquipedalian and amaryllis and floccinaucinihilipilificatrix. Periastron and tideline and paddereen and lucifugous. (I sometimes save the really good ones up for use as titles, or they somehow wind up supplying the entire plot of a work of fiction.)
But I like simple words, too, especially ones that are marvelously evocative of a time and place all by themselves, hard old Old English words or loan-words from other languages. Jarl and scop and hate and gild. I like onomatopoeia. Howl, scree, hush.
I like the rhythms and sound-patterns words make when you put them together. The hush of waves amongst the stones. Why amongst and not upon? Because amongst sounds like waves on a pebble beach. (I think that one's on The List as well.)
I like the subtle games you can play with them, with echoes and root words and meanings. There's a scene in The Stratford Man where words like raptor, rapture, rapt, rapacious show up a fair amount. Once per word, but there's a reason for it. They all come from a Latin root meaning to seize. Somebody has just made a rather bad bargain....
Some words are once-every-couple-of-books words (arrogate, for example) which you don't want to use too often but which you can probably recycle a few times in a career, and some of them are the sort of words that could become a personal tic if used, oh, more than once. (horripilation, which I found myself using in Patience & Fortitude, and was as delighted to have finally found the scene where it belonged as I was sad to realize that I probably wouldn't get to use it again.)
My drug of choice.