Books with well written antagonists.

I'm looking for books where the main character(s) actually interact with the antagonist throughout the story. Honestly, the closest I can remember for an example is Voldemort from the Harry Potter series, but I'm looking for something more direct, and preferably with slightly older characters rather than children. I don't really have a preference for genre, but I do love fantasy in general. I also like psychological themes, like between Will Graham and Hannibal Lecter in the NBC show (didn't watch the entire show because it was a little too dark for my preferences).

I'd prefer little to no romance, or if it exists, romance as a subplot instead of something driving the plot. Thanks!