Probably my favourite cinematic in recent history was the cinematic intro for Wrath of the Lich King by Blizzard. One of their slower pieces but that's why I liked it, with the sombre narration of the lead figures long dead father and the mournful music in the background it just did a great job in setting the mood and setting up Arthas as the expansions future villain.
By contrast can't say I really liked any of the cinematic for Diablo 3. They were pretty to watch but they all just felt so damned... soulless. Diablo 2 had these amazingly creepy narrated cinematic that had a great gothic feel to them. Diablo 3's cinematic while by far better looking visually were also just so very hollywood, for lack of better words. Nothing jumped out at me as memorable.
Ah well, probably just being grumpy. Can't wait for Heart of the Swarm though!