It's hard to say...Nietzsche sets a pretty high bar to match in the writer/philosophe tradition.
If you're not already familiar with them, you might like some of his predecessors like Schopenhauer (obviously), Voltaire (sorta-kinda-not really), Diderot (he's fun, but not as many new ideas), or, especially, Montaigne (who's great...no, i mean, he's Great).
There are also long-shot, off-hand thinkers like John Stuart Mill. Not a head-banging genius, but well written, interesting, and a good collate-r of ideas in his time and place.
More modern examples: Camus, Jung, later Wittgenstein.
Camus' prose is a bit stiff, but beautiful, and he has a few odd things to say, along with a lot of irritatingly relevant, moral kerfuffle.
Jung isn't a bad place to jump off from Nietzsche, but he'll take you in a very different direction. Similar themes, similar symbols, but very different goals, despite the similarity of their teleological descriptions. They have very different ideas about historical process.
Wittgenstein may have been the most original philosophical thinker in the 20th Century. His later writings are fragmentary and unclassifiable, but also brilliant and intriguing.
Two others that might be of interest are: E.M. Cioran and Walter Benjamin.
If anything, E.M. Cioran is too close to Nietzsche. An excellent writer, cynic, and wanton nihilist, in that order. Still, in his aphorisms, there are sparks of originality, and his insights cast long shadows on popularly held idols.
Walter Benjamin is a horse of a different color. He's a brilliant thinker whose admitted influences are Neo-Kantianism, Platonism, the Kabbala (he was operating during the 20's and 30's, so don't worry about his being a Madonna convert), Marxism, Jung, etc...etc...and yet, heeding many, he followed none. He's not a Nietzschean thinker, by any means, but there are occasional, unexpected touchstones. i have to admit, he's a particular favorite influence of mine that i feel is a bit neglected.
Other random recommendations: Douglas Hofstadter, Isaiah Berlin, Guy Davenport, Stanislav Lec, Paul Valery, Soren Kierkegaard...blah, blah, blah...