Well, I can't really pick just ONE song, so I'd say (in no particular order):
Big Caddy (Jay Tee sounds sneaky on this one...)
Bounce Bounce (funny and real)
We Bubble (w/ Baby Beesh--this could be a single, IMHO)
Beware, though: the way it works w/ 40 Ounce, my "favorites" change constantly (I often hear something in the twelth or thirteenth hearing of a song that I didn't hear before, etc). I'm sure that there's other 40 Ounce fans who feel the same way.
PEACE!