Not really having played either, I'll mention that Savage Worlds has far more Western and Space material, notably Deadlands and the PDF-only "Sci-Fi" toolkits on RPGNow. The rules explicitly have a thumb on the scales in the PC's favor, between "bennies" and the Wild Card die.
Typical Unisystem seems fairly gritty to me. If you want more cinematic combat, you'll probably want Cinematic Unisystem as implemented in Army of Darkness or Buffy the Vampire Slayer. Those games have fewer skills and less bookkeeping (also a feature of D&D 4). You could then adapt parts of the AFMBE supplements All Tomorrow's Zombies and Fistful o' Zombies for necessary bits of technology and livestock ... or with a little more work grab bits out of any GURPS or d20 books you have lying around.
"On two occasions I have been asked [by members of Parliament], 'Pray, Mr. Babbage, if you put into the machine wrong figures, will the right answers come out?' I am not able rightly to apprehend the kind of confusion of ideas that could provoke such a question."
- Charles Babbage (1791 - 1871)