Whenever I read John Updike or Joyce Carol Oates, I feel a gnawing sense of inadequacy when I come across words that A) I've never seen before, or 2) I've looked up at least once before and forgotten the definitions. Here are some examples from my recent reading:
exiguous: excessively scanty
exigency: that which is required in a particular situation or a state of affairs that makes urgent demands
desultory: marked by lack of a definite plan or not connected to the main subject or disappointing in progress, performance, or quality
cynosure: one who serves to direct or guide, or the center of attention
sinecure: an office or position that requires little or no work but that usually provides an income
Words like this are beautiful, but, at least among the people I interact with every day, aren't going to come up in conversation very often, even if I could remember them for more than 6 hours.
If you like this sort of thing, check out Wordsmith.org and their Word a Day section.