I like Shadowrun, but I'd have to recommend against it for both kinds of game you want. The main attraction of Shadowrun is its setting, and a lot of the mechanics relate to setting-specific things. The system isn't completely unworkable for what you want, but it certainly does nothing to help you. Not a 'universal' system.
I'm afraid I don't have better suggestions. White Wolf and GURPS could both be okay for the horror game. I'm sure there's better, but I don't have broad experience.