I first saw The Evil Dead on VHS, completely based on two things: the awesome cover art and the blurb from Stephen King that said "The most ferociously original horror film of the year..." I mean, I probably would have seen it anyway as my MO back in the day was just to rent every single movie from the horror and cult sections of the video store, but those two elements really put the movie to the front of the queue.
If I had seen this trailer it might have been rented even faster. I love the madcap quality of this original The Evil Dead trailer. It really sells the true movie, not shying away from some of the stranger stuff that Sam Raimi was doing (and would expand upon in Evil Dead II (losing a The and gaining a Dead By Dawn)). The trailer uses some really choice money shots, but I think that it also maintains enough mystery that as a kid I would have been endlessly intrigued... and probably thought it was a movie about a chainsaw massacre.
It's funny to revisit this trailer and remember a time when Ash wasn't a subculture hero for horror nerds, when he was just a guy in a movie who barely got anything to say in the trailer (and you wouldn't know that was him with the chainsaw if you didn't know that was him with the chainsaw). And it's great to look at this trailer and see that while Sam Raimi only started saying 'spook-a-blast' recently, he's been doing it since the beginning.