I don't like it when a deck of cards is supposed to be the centerpiece.
I absolutely love coins and jewelery. Anything shiny! xD
And high quality figurines are great. I was really pleased with the AC2 Ezio figurine. It was numbered too, which is really great.
Hardcover artbooks including both concept art and text. Must be more than just 20-30 pages.
USB filled with digital goodies. Wallpapers, soundclips, developer's diary etc.
Soundtrack CD is a must, with soundtrack cover.
Special cover for the game itself, plus new design on the game disc. Steelbooks are cool.
Posters would be great, but I don't like it when they are folded and adding them on the side in a tube would be a lot of hassle.
I could mention a lot more but most of it has already been mentioned by Gemini
