I've heard tarantulas are generally peaceful. I saw one once when I was vacationing in the Yucatan Peninsula, and it wanted nothing to do with humanoids -- it was scuttling away as fast as it could go.
You heard mostly correctly. The vast majority of "new world" tarantulas are quite docile and timid, going well out of their way to avoid contact with any potential predator (which includes humans). My 3 girls are all hand-tame.
"Old world" tarantulas, on the other hand are usually quite aggressive, temperamental, and cranky, and should never be handled. The same goes for most large Aussie spiders.