I play out only sporadically, and I take pride in being able to connect with my audience through the singing of an appropriate song for them, personally. If I bring my three ring binder and music stand along I suddenly have about twenty times more material to pick from. These are songs that I know very well, having spent at least several hours working out each one(and the proper typing out with chord symbols is an integral part of the preparation process).
When I'm singing one or two predesignated songs that night I pretty much always memorize, and my cohorts and I use notes more and more as the years go on. The secret is to use a BIG font which enables you to get away from the paper and project the song out well. It's better to use a stand than to hold the paper by hand and bury your face in it.