I've noticed that I have a few that get me every time. They are: water, river, lake, magic, and anything that implies winter, such as snow, frost, and of course, winter. Also, summer, lol.
I'm also attracted to covers that hint at these kind of stories. (I suppose it should be no surprise then, that my first book takes place in a town on a lake just as winter meets spring, so there's both snow, and rain.)
Here are some examples of books that had me drooling just from their titles and/or covers.
(^ I have so much love for this title, I can't even...)
What about you? What kind of titles or covers pique your interest?