Here's how I would rank them:
Used every session (or nearly so):
Concentration
Listen
Search
Spot
Used fairly regularly:
Bluff [5]
Climb
Disable Device
Hide
Knowledge (Arcana)
Open Lock
Sense Motive
Survival
Tumble
Used occasionally:
Appraise
Balance
Diplomacy
Heal [2]
Intimidate
Jump
Knowledge (most others)
Perform [3]
Ride
Sleight of Hand [4]
Spellcraft
Swim
Use Magic Device
Seen used once or twice:
Craft (mostly Trapmaking)
Decipher Script
Escape Artist [1]
Gather Information
Handle Animal
Profession (mostly Gambler)
Use Rope
NEVER seen used:
Disguise
Forgery
So overall, I would say that considering I've been running relatively conservative dungeon-heavy games for the last few years, my players make pretty good use of the skill system, and I do my best to reward them for it without being ridiculous, like those DMs you hear about who basically treat Bluff as a Suggestion spell. The only place where I would say I go out of my way to accomodate skills is that I try to make it useful, or at least interesting, to have Knowledge skills, my players mostly take care of the rest.
[1] - Escape Artist could come up a lot more, as one of my groups uses grappling a fair bit, but the people who use that option a) tend to have more Strength than Dex and B) are usually the ones interested in maintaining the grapple, not escaping it.
[2] - Probably should rank a bit higher, as until recently we almost always forgot about the Long-Term Care option. Its other uses come up surprisingly rarely.
[3] - A pretty good percentage of the times I've seen this used, it's been for Bardic Music.
[4] - Ranks so high because of one klepto PC. Without her this would drop to the "Never seen used" category.
[5] - Almost never for feinting in combat, interestingly enough. It's always been for BSing people.