Someone from my mom's Evangelical (Free Methodist) church was injured in the recent earthquake in Haiti, where she was working as a missionary. But it got me thinking...
Haiti is 80% Catholic and 16% Protestant (and, some would say, 100% vodou...). So are they going there to convert Catholics? Perhaps they are just going there because Haiti is the poorest country in the Western hemisphere (GDP per capita: US$1,900 -- compare to US' $47,000!). If they are going there to help jumpstart business and build infrastructure through donations, that's good, right? But if they are going there to try to convert people to their particular brand of Protestantism, they should start in the US.
When I think of missionary work, I mostly think of building houses and bridges and such and community organizing. A Maryknoll priest visited a local parish to solicit donations and told a story about bringing a community together. It seems that many of the Catholic missionaries these days actually primarily focus on evangelizing Catholics -- getting people to rediscover their faith, go to Mass and Confession -- rather than converting Protestants or non-Christians.
However, there has been work by Protestants, Catholics and Orthodox in countries that are not primary Christian (or post-Christian), that is among Muslims, Hindus, and Buddhists as well as in China. But I know many people realize that the most needed place for evangelization is the post-Christian West!
So, I would say there is a distinction between evangelization and broader missionary work. I think most missionaries are focused on economics these days.