Scot McKight has a great post dealing with this. The issue is the motivation of our hearts. It seems to me that doing something merely for the opportunity to talk about Jesus is somewhat of a bait and switch. "Here, let me show you 'love'...bam...here's a double-shot of the gospel!" Yet the other end of the spectrum refuses to mention Jesus because well...I'm not sure why - maybe they are just "good" humanists in church clothes.
Jesus was pretty concerned with how we treat one another, particularly the people who are treated poorly or who don't have a lot. And while I believe all people need to know the saving love of Jesus, I also believe that God is trying to reshape and mold our hearts in this life to be like Jesus. As part of that growth, God desires for us to actually have hearts for the poor, meaning that we love them whether they know Jesus or not. We love them because Jesus loves them. And if we can love them in such a way (or at least try to) then our authentic attempts to show them love will speak louder than any words (or tracts) we could share.
Otherwise, its like making folks sing for their supper...attend this worship service, or say this prayer and then we'll love you, feed you, insert your felt need here.
Bottom line, as McKnight says in his post, all we do we in the name of the Lord - for his sake and his purposes. And who knows maybe his purpose behind our good works is to give us a natural opportunity to authentically share our experience of the risen savior with the people we serve, I don't know that it should be our decision, but God's.
What are your thoughts on these things?