I thought that these forums need a thread dedicated to Silent Hill (horror fans as we are). Feel free to post any Silent Hill related questions/comments/etc. Here's my views/impressions on the series and please note that my experience on most of it is through me watching someone else play.
Silent Hill: Propably the scariest shit I've ever seen. I remember playing the demo when I was a kid and it scared me real bad. A random fact: Even though the grey children were replaced by mumblers in the PAL version, they were still present in the demo. Really creepy.
Silent Hill 2: I don't remember much from this game apart from the fact that it had really good music. James Sunderland is a really cool character.
Silent Hill 3: This has to be the second scariest SH, mostly because of the amusement park. Those goddamn bunny costumes still give me nightmares.
The Room: Not as scary as the earlier parts, but one of my favorite SH's to date. I really liked the ghosts and almost every other monster in this game. Mostly the ghosts.
0rigins: A really short game, but had the best main character. Storywise one of my favorites. I really hated the cow demons even though I was just watching
Homecoming: My first own SH. I find this game quite hard and it really is a friggin' scary game. Way scarier than Room or 0rigins. I also liked it that Pyramid Head made a comeback. This game didn't have a big variety of monsters though :/ I'm still waiting for the next one since there's much to improve. For one, I don't quite like the item/weapons menu. It sometimes actually gets me killed. There's some really good scares in this game and I REALLY like the shadowing.
Downpour: A really solid Silent Hill title. It's scary, the locations are really well made and the variety in pretty much everything, minus the monsters, is amazing. The game seemingly took some of the best sides in Shattered Memories, Homecoming and 0rigins and mixed them in. I totally love the fact that you now have the possibility to do side quests, it keeps the game going on for longer. The main character is one of the best thus far, too, and seems genuinely disturbed by what's happening. Now for the downsides: running around gets quite boring at times when absolutely nothing is happening, the variety in enemies isn't something to call home for and the game downright lags when there's a bunch of enemies. Konami is starting to get known for releasing games half finished.
Orphan/2/3: I really didn't know that a mobile phone game could have some scary moments. Now I do. These games are mostly puzzle solving and the battles are quite meh. On the other hand, SH's have always been good at puzzles
Arcade: I really wish they ported this. I really would love to see that.
Shattered Memories: Now that I have the game I can only say... wow. You have such a big map to explore and I actually got lost sometimes. Running from the creatures in Otherworld is scary at first but when you get used to it it kinda loses it's appeal... Don't get me wrong, it's still really fun and it gives some variation to the game. I still wish there'd be more scares outside the Otherworld. Puzzles in this game: top notch. If you like SH and have played the earlier games, give this one a try.
Those were my thoughts on the Silent Hill games and I'm looking forward to the next one. I also have to add that the movie didn't hurt the games as much as RE movies did to those games, at least in my opinion. I actually enjoyed the Silent Hill movie and I've seen it a lot of times. Silent Hills have always had a great story going on, some really creepy ass moments, really fitting music and as good documents as Resident Evil. I also love the multiple endings. One more thing are the comics and people who love Silent Hill should really read them since they capture the essence of Silent Hill in a really nice and twisted way.
Here's Silent Hill retrospective for those interested enough: http://www.gametrailers.com/video/gt-retrospective-silent-hill/10142 (don't mind that it's called "Silent Hill Movie")
Other games like this? Try Project Zero/Fatal Frame, ObsCure and Forbidden Siren.