Oh man, video game collections and small cars, i totally know that feel bro! I recall us (as in me and my older brother) having quite a bunch of small toy cars back in my early childhood, though it's possible that we have given them away now, can't really remember. Our video game collection, however, is greater than ever. Hell, there are even some games i haven't played yet.
(and also some games that are older than i am, which i personally find pretty rad)
As for other things of decadence, i'm not even that much into flights of fancy, but to say that i haven't bought a few things because I JUST HAD TO would be a lie. Allow me to put it like this:
The prime example here is probably the mouse, which is SUPPOSEDLY the only kind of left-handed mouse made for gaming (Razer claims so, anyways), and it wasn't particularly cheap (but it IS very good). My old mouse was still entirely functional, and quite nice too, although it was getting hideously greasy and was also mostly right-handed (ambidextrous shape with extra buttons for the right hand). The owl? I bought it because it's awesome. It's just staring at me, all day every day, with its awesome owlface. The little viking dude? I bought him because he's awesome too, and also because he's an ellipsoid like the owl. Other than that, i also have a few powerful laser pointers (300 mW for the most powerful red one, but it has lost its lens that allowed me to focus the beam :c), which generally don't serve me any other purpose than being neat.
Oh yeah, i also bought a super cool art-glass paperweight in Scotland. Why? Because it looked cool as hell. B|