In the movies objects throw with the force didn't seem to go very fast, notice Vader hit luke with some of these things and it didn't seem to break any bones or anything, Dooku made some rocks fall so I'd guess gravity would work better for damaging somebody.
About armor: Vader wears one, he can stop a heavy blaster (Han Solo's) with his hand, and I think the armor can deflect a lightsaber (if it's not a direct hit of course).
Movie Battles: http://homepage.ntlworld.com/richard.hart4/
Just a warning, It crashes a lot, at least for me. (don't worry razorace, MotF is much better, but this mod has interesting things :P)