I have to say that Hudson Taylor really impacted my life as a young girl. His story and committment to dress like the people made me want to do the same when I served with a people. I agree with Tracy that Amy Charmicael is another one, probably because I learned her story to retell it as a 1st person drama.
This might be cliche but I would have to say Jim and Elizabeth Elliot...their story is so amazing. It shows the power in forgiveness and God's grace and mercy, and it shows how how deeply Elizabeth felt God's calling for her to minister to those unreached by the Gospel
Gladys Aylward, Yes I like her too. I read the Ywam book about her. So much different than the movie. I know why she didn't like the movie. :) I really like stories about China.
I met Steve Saint. :)
My favorite missionary-sociolinguist hybrid is Kenneth Pike. I love his story because he was rejected from going to China as a young man. I don't know how I would handle that kind of rejection. My journey's been enough of a learning process even with all of the ridiculous grace and encouragement I've gotten. But, fortunately for sociolinguistics and for the Bible translation movement, God led Ken Pike to SIL and then Ken Pike coined "emic" and "etic" and did monolingual demonstrations... ugh... such a great story... :P