I have always believed that it's my duty to vote for the candidate that I actually want to have the position, at all levels of government; and I have voted in every election, local through national, in which I was eligible to vote, ever since I was old enough to vote. 
This is the very first election in which I have ever considered just not voting because I don't want ANY of the candidates to hold the office.
I can't, however, in all good conscience, stay home on election day. There are "down-ballot" races in which I definitely want a particular candidate to win.
I suppose I'll have to hold my nose and vote for Clinton. No, I do NOT want her to be President. However, I don't want Trump to be President a little more than I don't want Clinton to be President, and it may be a close race. It turns my stomach to have to make this kind of "choice".