I should preface this by saying that I'm new to adventure games; I picked up this and The Longest Journey a while ago and only just got around to playing this one. I can't believe I waited so long. This game has one of the best stories ever, no kidding. You wake up in an insane asylum, with no memory and no real idea what's going on. If the premise sounds cliche, I can promise that it only stays that way for about the first five minutes. And then you get to a twist, which I don't want to spoil, but it's awesome. The game trips constantly from hallucination to reality, and it constantly makes you question which is which, or if anything you're seeing is real at all. Trying to piece together the clues that the cutscenes and gameplay provide is immensely satisfying. The game also teases you by including some heavy symbolism in it's environments, and again, figuring out what it all means is a lot of fun. The puzzles are all quite logical (the main reason I went to the walkthroughs is because some of the items you need to pick up are really hard to see. There were also a couple of sound based puzzles that gave my tone-deaf ears some trouble).
Really, I can't recommend this one highly enough. The art, narrative, and gameplay combine in really extraordinary ways. If you like games as a storytelling medium, Sanitarium is really something you shouldn't miss.
BTW, I was able to run this on Vista without any crashes. I did hit a gamebreaking glitch during Chapter 5, though. Fortunately, starting a new save seems to fix that. You can find saves for the beginning of each chapter here: http://www.mediafire.com/?2zlx2by3ynz. If you hit a glitch just copy them to your save game folder, load the proper one up, and you should be fine :-)