wow, it's hard for me to pick favorites. And since I'm the music director at my church, I get to pick whatever I want the congregation to sing. I really try to pick what is appropriate for the scriptures and theme of the service. Sometimes that means singing a song that is not my favorite, or picking a song that I know certain members of the congregation won't like. It's an opportunity for education; When someone tells me that they didn't like a particular song that we've sung, I get to say "well, it's a good thing we're not worshipping you then, isn't it?" My congregation is discovering that it's not about singing "favorite" songs, but about directing our worship, concentrating on some aspect of God, or reinforcing scripture.
All that to say I don't necessarily have favorites. I do find myself drawn to Twila Paris songs, like "All That I Need" and "He is Exalted." I also like "We are an Offering" "Open the Eyes of My Heart" and "When It's All Been Said and Done."