The one with the infamous "Bang, bang, bang!" shouting and Ocelot dance. It was the only one that was pre-rendered aswell due to how long it was.
Or maybe it was classed as 90 minutes since it was a new cutscene directly afterwards, and just that one itself was 45... I COULD be wrong.
There's actually two cutscenes that are pre-rendered in MGS4; that one and the one that plays immediately after the microwave sequence. It has nothing to do with how long they were and everything to do with the fact that they were handling large numbers of character models.
Where they skippable ? I'm replaying the single player of Max Payne 3 and it's frankly becoming umbearable.
The difference in quality between the beatiful gameplay and the cutscenes is striking.
With the exception of the small bit that occurs just before the proper credits, every cutscene is skippable.