I'm compiling a list of spells that either make investing ranks into a skill irrelevant, or provide a significant boost to the skill check. Please contribute as you think of suggestions.
Great idea!
...Still I'm here more like the devil's advocate...
I will be the one to provide the counter arguments
So.. lets see...
.....
Any Skill: Spells
Divine Insight
Standard Skills: Spells
Appraise: Legend Lore (significant items)
No. Legend Lore does not replace appraise no matter how you put it. Only works for "legendary" things, has a lasting casting time and, most importantly... does not give away price.
Again lets not forget the phrase: "If the person, place, or thing is not of legendary importance, you gain no information."
Which... kind of narrows it down... a lot.
Balance: Fly
Sure (See "*" at the end)
Bluff: Glibness
Correct... very powerful spell, unfortunately reserved for bards (and assassins) only.
Climb: Spider Climb, Alter Self, Balancing Lorecall
Sure (See "*" at the end)
Concentration
Craft: Magecraft
Decipher Script: Comprehend Languages, Read Magic
Yes... a Comprehend Languages Scrolls has saved many a lives. Still... (See "*" at the end)
Diplomacy: Suggestion, Charm Person
Sure (See "*" at the end)
Disable Device
Disguise: Disguise Self
Now now... Not true. Why? When a character disguises there is no middle ground between success and failure. They either notice you or they don't. Failure in disguise, usually, has VERY nasty consequences. This means that one cannot risk much... otherwise he will not live long to tell about it. A simple +10 given by Disguise Self, or Alter Self can help A LOT indeed... but without a strong disguise skill and the appropriate skill tricks one will not make it. Don't forget that a simple cantrip (detect magic) can always ruin any magical disguise, while the mundane one has nothing to worry about except for a strong spot.
Undisputedly, the base for success is a strong skill and the relevant skill tricks, equipment and synergies.
The spells come in VERY very handy for those with a strong skill (Alter Self can even mimic vocal cords!)... but otherwise do not serve an untrained character much.... Oh and another factor... : Duration. Sometimes you have to stay under cover for a LONG time.
Escape Artist: Grease, Knock, Freedom of Movement
Sure (See "*" at the end)
Forgery: Amanuesis (Duplicating documents)
Not really. INMO, If the spell was to be used so as to fool someone, they would have given a DC or some sort of text about it. It simply copies text to save time. Nothing more nothing less.
Even so, if one takes the "This spell copies 250 words per minute and creates a perfect duplicate of the original." to the letter without giving notice to RAI, he should be aware of the following:
Official documents, important parchments, books etc. (where forgery is used 99% of the time) almost always carry signatures, insignias stamps, sigils, family crests, illustrations etc. Even the paper matters.
So I don't see how Amanuesis can replace Forgery...
Gather Information: Legend Lore
I would love it if Legend Lore could wash my dishes... but unfortunately is does not. Again, the spell cannot provide the benefits of Gather Information.
Handle Animal: Charm Animal, Speak with Animals
Hmm... The spells are perhaps even better that the skill... for situational situations . Still, those who take ranks in the skill do it for the purpose of training, in which case the spells are useless.
Heal: Cure Light Wounds, Neutralize Poison
Ok you win
Hide: Invisiblity
Invisibility makes the Hide skill meaningless.
With all respect to dear Greenfield, this is as wrong as it can get.
I 'd even say its the other way around...
A good hide skill alongside the proper feats and HIPSs, makes Invisibility meaningless.
Staying hidden/invisible/unnoticed, like it or not, is a thing reserved for the skill monkey.
First off, something people mostly forget: Invisibility is useless if you can't keep quiet!!! ...meaning that you ALSO need to be good at moving silently. And if you ARE good at move silently, it means that you are also good at Hide... which means that you don't need invisibility
Secondly, Invisibility is only good for fooling around until level 5 or so... for there are SO many things that can see through the spell... its actually ridiculous.
In order to overcome most of the detections out there, be that magical or sensory, a character has to devote plenty of levels, feats, and skill ranks to the single profession of remaining unnoticed. And always, the base of the above is none other than strong stealth skills (Hide+Move Silently). You always build on top of those two maxed out.
...I'm getting carried away... And perhaps at this point I should give Invisibility the respect it deserves. So here it comes:
Invisibility is a great GREAT spell! One of my favorites actually!!!
Still... if a character wants to play the "invisible" type. Invisibility is NOT the solution.
Intimidate: Cause Fear
Ummm... NO. Just read the spell description and then the skill description.
Jump: Jump (spell), Fly, Alter Self
Sure (See "*" at the end)
Knowledge: Commune, Contact Other Plane, Legend Lore
Legend lore again... *sigh*... not really. Even Commune and Contact other Plane cannot really do the job because of the monolectic responses of yes, no and maybe...
Still I won't argue much, cause in certain situations the spells will be perfect for the job... while in other cases they will be useless and the skill will pull through... So.. its a tie.
Listen: Tremorsense
Yes. For detecting stealthy creatures and characters it is really good. However it only covers 30 feet.
Anyway, listen is not really effective for taking down characters+creatures devoted to stealth. I've yet to see someone max out his Listen skill...
Listen serves for plenty of other things. Tremorsense is simply a 30 feet detection spell.
Move Silently: Silence
Umm no... no .... NO!!!
I've yet to hear of an infiltrator, a spy, a scout who is completely deaf!!! 
Open Lock: Knock
Sure (See "*" at the end)
Perform
Profession
Ride: Mount, Teleport
Mount ? Please read the spell, and then the skill!!!
? Teleport ? Since when does teleport help one fight while mounted??
Other than that sure.... I'd rather have teleport than a good ride skill
(*sigh* Both are completely irrelevant)
Search: Locate Object (If known), Summon Monster I (finding traps)
Funny
NO. Search does more than those spells combined. Just read the skill text.
Search is really hard to beat.
Sense Motive: Zone of Truth, Discern Lies
Sure (See "*" at the end)
Sleight Of Hand
Speak Language: Tongues
Sure (See "*" at the end)
Spellcraft: Identify (item identification)
I don't see the point of that... Spellcraft is not a skill that can be replaced by a spell, but a skill that works with spells...
No?
Spot: Prying Eyes, Tremorsense
Yes, Prying Eyes does more than cover for spot, in some cases... For tremorsense see above.
Still, not even prying eyes can cover for spot as a whole, especially for those personal (often opposed) checks.
Survival: Discern Location (for tracking), Create Food and Water (for food gathering), Know Direction (for finding true north), Find the Path (safe travel)
Sure (See "*" at the end)
One remark: Even for a spell as powerful as Discern Location, you must have seen the subject at least once. That is a big deal. Survival simply finds someone, no matter whether you have seen him or not.
Swim: Alter Self, Water Walk (Crossing water)
Sure (See "*" at the end)
Tumble
Use Magic Device
Use Rope
.....
..... So, time to explain the asterisk (*)
Well... if you finally find yourself with the following spells memorized/prepared:
Legend Lore, Spide Climb, Balancing Lorecall, Comprehend Languages, Suggestion, Charm Person, Cause Fear, Jump, Knock, Legend Lore (again), Mount, Discern lies, Know Direction, Water Walk, Disguise Self, Charm Animal, Silence, Tongues, Invisibility, Commune, Contact other Plane... Legend Lore (again)....
its time to ask yourself.... Why the hell aren't you playing a skill monkey?
