well, i like hard sci-fi la arthur clarke, paul anderson & greg bear (and stephen baxter and iain banks and gregory benford...). came to think of it, why are best hard-sci-fi authors in the bookshelfs from a-c? ok, kim stanley robinson is the exception, but not many others. hmmm, larry niven... anyway, if you are looking for sci-fi - horror - fantasy - space opera, check peter hamilton's "night's down" trilogy.