This game is a classic. Probably the number 1 reason why I work in the videogames industry. If you are a complete stranger to point&click games, buy it ASAP. It's a must have, and probably the first step you should take in this genre (along with pretty much any point&click from the Lucas Arts golden era). The Special Edition doesn't bring anything new but graphics and voices, yet it's still worth every penny because it's an insane amount of funny quotes and silly situations to solve. The OST is pure gold, and even better in the Special Edition.
I honestly don't know what to say against this game, except maybe it's a bit short for nowadays standards (keep in mind I've finished this game at least a dozen times already, I'm still not bored of it but I kind of know every puzzle by heart now). I guess some people could complain about the new graphics but if they do, they can switch to the original style anyway... I'll end my review with this quote, taken directly from the game itself:
"Never pay more than 20 bucks for a videogame."
...Oh, and look behind you! A three-headed monkey!