Half Life on Dreamcast, but it did get released much later as a iso file but it was clear the game hadn't undergone final optimisations etc.

Shenmue 3 of course.

I didn't know Bulletstorm 2 was cancelled, that's a shame. That game was awesome.

I don't think a ZombiU 2 or Bioshock Vita will happen

Also 8 days and the getaway 3.

Not necessarily a cancellation, but rare on Xbox is a huge disappointment

Resident Evil PSP back then had me. Figured out they moved it to the 3DS later.
Banjo-threeie too ..

Shadow of the Eternals for WiiU
I have been waiting for a sequel to Eternal Darkness since 2002. Nintendo should have backed this one.

Sadness for Wii
Had potential to be a truly innovative game. I still have hopes someone will do a game like this.

Baldur's Gate III *smash fist into wall* dammit!

Final Fantasy 64, Dinosaur Planet and Banjo-Threeie

Shenmue 3

still holding the faith that it happens.......................someday........I'd buy any console to play that

Warcraft Adventures Lord of the Clans: http://en.wikipedia.org/wiki/Warcraft_Adventures:_Lord_of_the_Clans

Sam & Max: Freelance Police: http://en.wikipedia.org/wiki/Sam_%26_Max:_Freelance_Police

Full Throttle: Hell on Wheels

And Project Offset

I know man, I know!