Stonefoot isn't very good, IMO. Since you have so many low level stances, any sort of utility options that are really handy when you can use them but otherwise not worth switching your main stance(s) for are ideal. Because you can only have one stance up at a time, so it's silly to pick a bunch of "decent but not as good as my default" stances. Get the funky ones that give truly unique abilities. On that note:
I like Step of the Wind a lot. Even if you never utilize it for the combat maneuver bonus (and it gives a more general +2 to hit aside from that anyway), just the ability to ignore difficult terrain can be very helpful.
Flame's Blessing, if you plan to keep your tumble ranks maxed, is decent fire res, though the stance is pretty mediocre till level 16, when it's suddenly giving you fire immunity.
Hunter's Stance is excellent for the new form of detection you get. Again, the only thing is it becomes kinda redundant if you later take Hearing the Air. Well, that and you basically have to waste a maneuver known on Wolf Fang Strike to qualify for it.
Child of Shadow is a very good stance, too, and a great "I walk around with this one up" choice until you pick up Absolute Steel. Island of Blades is probably the next best pick after all the ones already mentioned. It's not great, but it's something.
Every other stance option I'd rank much lower than the ones mentioned above (Stonefoot, Clarity, and and Blood in the Water).