I think the fundamental question is 'Does you DM call for the skill?'
If he does, it is useful.
If he doesn't, it isn't.
My mouth is dropping to hear people consider balance a poor skill. I find myself calling for balance checks ALL THE TIME.
You do realize that a DC 5 balance check is required any time that a character must traverse a slope or uneven terrain? Normally, unless the armor check penalty results in more than a -5 penalty, the character may make take 10 on the check, and carefully make his way across such slopes without difficulty. But what about in combat? What about when making double moves?
Then in my campaign you make a balance check. And if your clumsy dex 9 cleric in full plate stumbles and finishes his move on his backside, well tough. And if he ends up rolling down the hill, that's too bad. You had to choose between protection and mobility, and you choose protection.
Have any of you actually done any caving before? Do any of you go hiking? Have any of you actually taken a walk in the woods off the trail? Please don't tell me how unimportant balance is. Please don't tell me how silly it is to call for balance checks when hustling across uneven terrain with 60-100 lbs. of gear, and trying to avoid getting axed by an orc. And frankly it is silly to complain how useless a skill is just because you don't want to deal with the consequences.
Not to mention I as a DM and fond of devising obstacles that will call for balance checks:
Ford the raging river - DC 10
Cross the room filled with clay statuettes - DC 5
Traverse the slimy moss covered slope in the funnel shaped room - DC 10
Cross a broken portion of a mountain trail without falling down the cliff. - DC 5
Cross the log used to bridge the stream. - DC 0 (can't take 10 unless you crawl)
If you aren't calling for balance checks, why don't you just throw away that whole armor check penalty thing?
Use rope gets called for a good deal less often, but a failed use rope check often results in character death.
Force the party to start making choices between flying to avoid a climb, balance, use rope, etc. check and keeping a fly resource ready in the event of a flying ranged attack monster and you will see them start to appreciate a broader range of skills.
As for Appraise, this is another skill that I call for all the time that causes my mouth to drop open when it is said to be useless? How do you know whether you are buying a masterwork weapon or merely an overpriced ordinary one if you can't pass an appraise check? How do you know what to carry out of the dungeon if you can't tell cut glass from gemstones? How do you know that clay statuette is the work of a famous master artisan and worth more than the silver statuette beside it if not for the appraise skill? How do you know that the guy you are selling the loot to isn't ripping you off in a huge way if you can't pass an appraise check? Don't go accusing the skill of being useless if what you really mean is that you don't want to deal with the consequences of the skill.
In my campaign, appraise comes up a heck of alot more than spellcraft, and balance is more generally useful than tumble.
I can agree with Intuit Direction. This is one of those skills like 'perform' or 'gather information' that the DM really has to work to incorporate into the average adventure. Sometimes you have to do that. Prepare lists of rumors for each module so that good 'gather information' checks do result in useful knowledge. Incorporate 'perform' in cunning ways or give oppurtunity for the skill in RP outlets. If you do, the party will start to see situations when a Bard could have been helpful. Intuit Direction is really narrow though.
There is a VERY good article on the Profession skill in a recent Asgard that EVERYONE who DM's should read.
I tend to allow Profession skills to be broadly defined. If for instance you had Profesion (Sailor) and I made a call for a Use Rope skill check, and you said 'I don't have that, but I do have 5 ranks of Profession (Sailor).' I would certainly respond, 'Ok, you can substitute that but the DC will be a little higher because rope use is only part of your training as sailor.' Then I'd add +5 or +10 to the DC depending on how important I think the skill is to the overall profession. I would happily allow Profession (Sailor) to be substituted for related craft skills like Craft (Carpentry), Craft (Shipwright), Craft (Net Weaver), and Intuit Direction, and in some cases (namely, when aboard a ship) Weather Sense, Climb, and Balance. All that changes is I add 5 or 10 to the DC. A few well chosen points in profession skills will cover alot of ground.
