Vader's death
 

I have been thinking about this for a few weeks now. What was it that actually killed Vader? Was it Luke cutting off his hand(seems kind of silly), or could it have been the surge of electricity from when he picked up the Emperor? The second scenario seems more palatable. but wouldn't the electricity have killed him instantly? Maybe it fried his machine parts or something?

I think the Emperor's Force Lightning fucked up his life support systems. So he wouldn't have died immediately, but Luke wouldn't have been able to save him either.

Luke taking his mask off just hurried up the process.

Easy answer: The Emperor was giving Luke shots of energy intended to kill him - when Vader grabbed the Emperor, those death rays hit Vader full-force and at close range. They probably also (as the other poster mentioned) messed up the machinery keeping him alive.

I think this is very obvious..

I also have a theory that Palpatine uses the force to "stop Anakin from dying." When Vader decides to kill the Emperor, he in essence sacrifices his life to save Luke and the rest of the Republic.

This may be covered in RoTS, but I haven't heard any spoilers on the matter.

He was gasping for air after getting his hand cut. So maybe Luke screwed up his machinery.

Also, I wonder how Lucas will explain the dead Jedis dissapearing in ep 4-6 but not in 1-2

http://www.theforce.net/swtc/injuries.html

Goes into as much detail as possible.

Also, Lucas has said for the past 5 years that he will explain why some Jedis disappear and others don't in this film.

Wow some people have really thought about this.

Who wants to bet that the explanation for the Jedi disappearing trick is going to be something totally STUPID? (can anyone say midi-chlorians?)

Damn, you're not kidding!

Already been done. check out the commentary on the original trilogy DVDs

Except for that those explanations were made before the DVD set was released, so there are at least two changes I've noticed. It said something about Anakin still having eyebrows, which he now doesn't.

Also something about him being extremely tall, because you could see his skeleton thru the suit when he was getting electrocuted when he picked up the emperor. Plus the spirit Anakin was a lot taller than Obi-Wan. I just noticed that not only did they replace Anakin's head with a younger one (yeah, still Shaw's body there), but they also reduced his proportionate height to Obi-Wan's.

from the injuries site above:

http://www.theforce.net/swtc/Pix/cards/wide/rotj143.jpg

from an old DVDTalk post:
http://img24.exs.cx/img24/6352/rotj-remaster2.png

See how much shorter Anakin now is? If you look at their feet, they weren't really lined up before as well. Anakin was like two feet taller than Obi-Wan before, now only a few inches taller, which is more realistic. I actually like the new version a lot better. He just looked huge in the old version, plus I'm one that loves the prequels so I'm all for continuity. I'm sure all you haters will agree come May 2005.

Aren't those Tops Cards cool, I've got them as well

Anakin wasn't huge in the original version -- just standing closer to Luke

they are actually must closer in height, if you look close enough you see that anikan is standing in from on obi wan by a good bit, thus making him appear taller

Yeah, yeah, OK, I see that now. But in the new version, I think they're both standing the same difference from Luke. And yeah, that is a Topps trading card pic I got from that site.