I'm not sure if this was official or a rumor since it was a while back but....

Earthbound 64, I was so looking forward to that the entire time I owned a damn 64 and it just never ever came.

StarCraft: Ghost.... =( I was downright obsessed with that game, then it kept getting delayed, got a new developer before it was done... and now it has disappeared

The game didn't get cancelled so much as it just sort of dropped off the radar and faded away, but I was looking forward to Freedom Fighters 2: The light squad-based gameplay of the first one was a lot of fun, even if the game was short.

^what you mean they really wanted to make a FF2 and didnt?well that sucks

^
That's right. A sequel was announced at some point in time, but there was next to nothing said about it after that - no concept art, no targeted release date, no cancellation, nothing.