Gorm Hareth:
I tend to just use passive perception, all that guessing of when to roll isn't really worth the time.
Honestly me too, but in my games you can explicitly look for things and roll perception, and if you're looking for something in particular you get a lower CR to actually see it.
For instance, you might need a 15 perception (passive or otherwise) to notice a giant spider on the ceiling if you're just looking in the room generally, but if you specifically say "PC looks at the ceiling for something" then you might only need a 5 or automatically succeed.
I generally roll for something in any case - either a stealth roll vs. passive perception or a perception check vs. a CR. I don't like that PCs with high passive perception just automatically notice everything.
And yes, it's on my list to create another OOC thread - soon ;)