Really? Granted, I haven't heard any of their other albums besides The Con (that will change tomorrow), but I don't think Nineteen is anywhere near the best song on the album - at least, not now I don't.
Personally, it's not only my favorite T&S song, it's probably one of my favorite songs period. I also really like "The Con" and "Are you ten years ago" most off that album. Nineteen really hits for me.