I think every CE done by Blizzard is just amazing!
Diablo II CE
World of Warcraft CE (and expansions)
I hope there will be a Diablo III CE as well as the next WoW expansion (by the way, I've never played WoW, I do however love the CE goodies
The Ultima IX CE was great, especially since it included Ultima I - VIII + Akalabeth!
Most recently, I have to admit that the Bioshock 2 CE is special. Huge, and unique!
As for most disappointing CE, I would have to say Oblivion. Supposedly it had a nicer packaging and some (cheaply made) coin (who cares) plus a making-of DVD... big yippee.
cheers,
-astropi