Depends on your playstyle. Recently I'm quite fond of Fadeleaf, to teleport either myself or an enemy out so I can avoid getting into a jam. Also nice that it has a very low charge cost
I expect that fadeleaf is a pretty popular footwear of nature effect, given how popular phase shift was before I changed it to not work so well on the player.
I feel that, having a good option to disengage as a backup is always great. And as a warden player I get the bonus of knowing exactly where I'll end up.
I enjoy blindweed, since it's basically a free win against a mob of your choice. Evil Eye charging? Blindweed to stop the charge. Scorpio? Blindweed, now you can actually approach them and get free hits on them. Warlock? Blindweed to stop them from shooting at you.
Blind makes them not see you, cripple makes them lose track of you and also facilitates free hits, even in melee.
With warden it's basically invisibility on demand, which is super nice as well.