http://starwars.wikia.com/wiki/Vibroblade
Vibro-weapons are bladed weapons of varying types that use micro-vibrating blades to cause greater damage with less force on the user's part. As mentioned, depending on the time period they commonly are treated with a Cortosis weave, which is a Lightsaber resistant material.
You guys are -all- correct concerning combat armors. There were even heavier armors in use as well that offered true resistance to higher-yield blasterfire, but obviously it's never really seen in the movies. Except arguably Boba Fett's. And I don't think he ever takes a blasterbolt on screen.