My main Living Greyhawk character has had 4 ranks of climb since 3rd level (he started with two) and he's never regretted having them. In fact, he's actually used climb on a half dozen occasions or so. (And in most of them, he was the only character who could make the climbs unaided.)
Despite being a wizard himself (ftr 2/wiz 5 at the moment), he's never been able to rely upon spider climb, levitate, etc. After all, the spider climb in his spellbook could have been shield, protection from evil, true strike, or burning hands. The levitate could have been bull's strength, flaming sphere, or glitterdust. At his next level, he plans to pick up fly but he still wouldn't use the spell to climb a tree or a cliff he could climb without magic. After all, he might need the fly spell for a combat later in the day. The less resources he expends upon overcoming an obstacle, the better.
Similarly, the opportunity cost of skill boosting or replacing items has simply been too great for him to buy slippers of spider climbing or something like that. He'd rather have a headband of intellect +2 (that gives him one extra haste spell per day and boosts his DCs). He'd rather have a magic weapon. He'd rather have a +2 mithril chain shirt. He'd rather have an amulet of natural armor.
That being said, he'll probably invest in a few cheap scrolls of spider climb and jump just in case. . . .