This question has been asked in the past:
http://collectorsedition.org/forums/...ighlight=worse
But it's good to do an update.
The current worst Collector's editions are:
Need for speed hot pursit limited edition, The normal case with limited edition written on the front cover, only included DLC codes inside.
Tron special edition - The art work was diffeent on the front cover, but it doesn't have a single thing to indicate it was a special edition. Came with DLC codes on a card.
In fact pretty much all the EA special edition with DLC code only that weren't pre-order versions.
The Best ones would be:
Bayonetta Climax edition Austrailian version - unlike the Euro version came with a Fair Replica Gun in one large Box.
Bioshock 2 collector's edition -one of the most unique edition, came with both a CD and Vinyl soundtrack and detailed touches such as velvet for the case holder was very nice
Gran turismo Signature Edition - Wonderful attention to detail and sheer content. All in a very nice unquie shaped black case.
Assassin Creed Brotherhood Codex edition - Sheer amount of content and nice case design.
God of War 3 ultimate trilogy edition - Not the USA version, this one came with the two remastered prequels. Nice box design again with velvet interior.
Starcraft 2 Collector's edition - Contents and box design. USB sticker was very nice