Perception checks

[GnomeBoy]

I would just use :
Intelligence - when you're actively searching/looking around/trying to listen to something
Luck - when you're not
Personality - when you're trying to see if the guy's hiding something/is nervous/is a disguised spy

Further:

Strength - when you inadvertently lean up against the secret door because you're tired of looking for it.
Agility - when you're bouncing off the walls.
Stamina - when you take all day to search for something hidden.

But seriously, it could be any of the attributes, based on the circumstances (what is it that's being perceived), the people or person doing it (I know a thing or two about where they might keep such things; I am an ostler, after all), or whatever it is that makes it non-obvious.

Often I just make it a "gimme" (rather than a roll) for a particular character, if whatever it is is in their realm of expertise...

[Anselyn]

What ability goes with spotting things? Immediately we can through out Strength, Agility and Stamina.

According to page 53 (bottom right) the Key Abililty is Intelligence.

Searching and spotting: Intelligence

Talking in [3.X] terms, Wisdom describes Perception/Intuition and Willpower: in DCC Perception/Intuition merge into Intelligence, Willpower merges into Personality.

Sherlock Holmes is intelligent not lucky.

The myopic wizard has probably previously rolled on the corruption table.