I canceled my pre-order of the collector's edition after some "deep thinking" on the porcelain throne.
-Behind the scenes dvd/blu-ray: probably only watch once.
-Diablo Skull: Neat-o! More crap for my desk (already have games).
-WoW Pet: I don't play WoW.
-B.Net Portraits: Yay?
-D3 Ingame Dye/Wing: I actually like these and probably the only things I want from the pack. But as with every promo cosmetic, they will end up replaced a week or so later for something with more sparkles.
"Hey but that's just like your opinion man!"
I know some hardcore Diablo fans will love these but it seems like a lot of people whom just want to play the game are snatching these up just "because". Reselling the Collector's Edition to make a few extra bucks is another story and who knows how flooded the market will be once everyone has the product on hand (the time it takes to list, sell and ship the game you could be playing D3!
In the end, just ask yourself if the extras in the collector's edition are worth the additional $40.
Now if it had included a 6" Diablo resin figure that would be a completely different story