6cm x 6cm

A lot of pinholers do get completely obsessed with their gear to the same degree that Leicaphiles do. But at that point, it's about gear fetishism, which has nothing to do with making photographs. (Which is no less valid as a hobby than photography, just not really related IMO.)

But! Pinholes do impart their own unique characteristics to both the process (VERY different experience) and the end result. If it's not for you, great--go with whatever makes you happy!--I'd just be wary of throwing the baby out with the bath water, which is easy to do when something is surrounded by fetishism. For example, the fact that the Lomographic Society has created a bunch of drooling drones reciting their marketing spew to anyone who will listen doesn't mean that the Lomo LC-A isn't capable of producing some sweet and unique results. Even though the surrounding hype makes me want to peel my own scalp off, I like what I can get out of it the camera.

Same goes for pinholes: about half of what I shoot is with a pinhole. I bought my primary pinhole camera ready-made and don't feel the least bit bad about it. I only make them when I want a different result that what it can provide.