Well, the only gory deaths I could laugh about and which I could therefore consider "enjoyable" were the ones in Braindead. ^^

Other than that, I consider the deaths in the first two final destination movies extremely original, especially the one of the woman in the kitchen.
(I haven't seen the third movie yet)

But if you stop considering only movies, I would say the "funniest" deaths are the ones in Happy Tree Friends.

(It really scares me that I enjoyed watching sick stuff like Braindead and Happy Tree Friends... :s )
I would say that generally unrealistic gory scenes don't bother me (like in most video games), but realistic ones do.
I felt very uncomfortable during the scene in American History X. :/
Other really horrible scenes are the ones in Irreversible, a movie I really don't want to watch a second time. One is gory, the other is not, but is even more unsustainable.