I have a few jerseys, but I've never felt really comfortable in them. As a 250# clyde, any shirt which clings to my belly just reminds me that I'm fat, also it generally creeps upwards (and that includes cycling jerseys).

I prefer a loose synthetic tech tee. Aero be dammed! If I lost 80lb and had a six-pack to show off, I might like a tight-fitting shirt. Meanwhile I need to flap in the breeze!

Golf shirt is a good idea too. I've often thought that the couple golf shirts I have would perform well in athletic situations, although I'm not sure I could get used to the feel of the collar.