Collectors editions have an appeal, mind you, and a strong one for me. I love the idea of having a quiver of arrows hanging on my (still in planning stages) game room wall, or a statue of Batman standing guard over my collection of games. But I don't and there's a few reasons why.
While I'm certain this doesn't apply to every game (my sample is of convenience, not randomness) I've heard some disappointing things about many collectors editions in terms of the quality of the bonus items. Batman: AA had plastic batarangs, Halo:Reach's figures had a cheaper stand and fragile figures, and there are a couple others that I won't enumerate. Why would I pay up to $70 for what amounts to action-less action figures that are less detailed and more fragile than the regular action figures?
2) Lasting Value
While the CE bonus swag is pretty slick there's no guarantee I'm going to love the game. If this happens I've got buku bucks locked up in a commemorative item that has little resale value and holds no positive sentiments for me. Even if this doesn't happen, I don't love a game 'till death do us part' - in 10 years are the items going to mean anything to me? Or is it going to be a RC Warthog or Spartan helmet that just sits there without evoking any sort of emotional response from me? Personally I doubt it - things I loved even five years ago have lost the same reactive nature with me and spend a lot of time collecting dust.
The bonus content doesn't serve any real purpose other than to look nice sitting a shelf. A video game is superior to a movie because of the interaction the player has with the game. So why is bonus content for an immersive, responsive piece of entertainment a static, emotionally shallow object?
Now, there's nothing wrong with the bonus content - but to me, the cost of ownership vastly outweighs what little benefit there is.