Having gotten linked to this article for other reasons, I was interested to see that Space Quest (tragically as it is that I haven't played it) managed to make the top spot of having the most creative death scenes in the first three titles, at least.
http://www.wired.com/geekdad/2009/10/10-of-the-most-creative-video-game-deaths-ever/
I must agree with that article. I've played all the games, and I must say that out of all of them, the death sequences are at their prime in games I-III. By the way, you can play the first two on Sarien.net. I highly suggest you do.