To sum my post up - I DONT KNOW!!!
I totally agree with that. I know this is a lamo answer, but I seriously don't have a fave FM song. I like, or love, pretty much everything they've done...so can't narrow it down. I think Sisters Of The Moon is an awesome Stevie tune. Chris' Songbird and YMLF always get me. Linds' can do very little wrong
...so my answer would be:
I DONT KNOW!!!