Worgen is best for any druid (Alli) spec except for resto, in which case NE would be better for Shadowmeld.
Resto: Meld is great for dropping focus off you and keeping you alive. NE is easily the best.
Balance: Extra crit and mobility is much better than meld, considering your survivability is already pretty good.
Feral: Again, extra crit, but worgen sprint gives insane ToT in cat form, which is especially useful against other druid FC's (travel form will outrun cat).