Even though it's not my favorite, SH1, as the first 'experience' with the series, was amazing. At the time (spring 1999) there simply wasn't anything like it. Sure, it could aesthetically be passed off as 'Konami's RE clone' from early screenshots, but even the very first moments of this game seperate it by miles from RE.
SH1 is great to start, if you can get past the dated graphics.
SH2 is the stand-out game of the series, though. It has a 'Twilight Zone'-esque approach (having nothing to do with SH1 other than minor elements) and is very much a psychological character study- not just on the central character James, but on every character. While not as outright 'scary' as SH1, it's far more moody and depressing. To this day I'm still impressed by the graphics. Personally, I'd save this game for last. Never before have I felt so emotionally drained after finishing a game- and I consider that a good thing in the case of SH2. It's very powerful, albeit a bit slow to start.
SH3 is much more faithful to SH1. It's directly connected to SH1 and has a similar 'frantic fear' of the first one. It's more about scaring you (again, in dark imagery, creepy sounds, and bizarre & occassionally relentless creatures as opposed to the RE-method of 'scary'- cheap thrills and jump-out scares) than the creeping, emotional desperation of the second game. The graphics are excellent and the 'effects' are among the series (and PS2's) best. Some, like the 'alternate' Brookhaven Hospital, are literally jaw-dropping. Story-wise it's pretty good, with some nice, twisted additions, but following such a personal story like SH2, it definitely feels like step down. Great game. I'd play it after finishing SH1.
SH4 is kind of the black sheep of the series. Originally intended to be a completely seperate game based on traditional Japanese horror (the project was simply called 'Room 302'), early in production it was changed to be a Silent Hill... and it shows. Conceptually, I think this game is brilliant- but it definitely stands out next to it's previous 3 entries. The game is dreary and dream-like, dealing with some very interesting ideas, but, due to a complete shift in scope for the team and cut-off production time, the game doesn't really touch a lot of the potential that you can definitely see from the get-go. Gone are some of the basic aesthetics of SH- significant darkness, barely illuminated by a flashlight, the infamous radio, the lonely, foggy streets of Silent Hill. Even though SH4 has two fairly significant locations in Silent Hill, the bulk of the game takes place in a neighboring town of Asheville.
I think as an 'experiment' for Team Silent, the game is fantastic- and when you really dig into the story, the reason for the characters, and the creations of the antagonist, there is a very fascinating, sad story (granted you get the 21 Sacraments ending
). Again, there is still a pretty overwhelming feeling that they weren't given enough time with this game and a LOT of potential was untouched. I wonder how this game would have turned out if it would have remained the side-project 'Room 302'? I would play this third, almost as a set-up for SH2.
Also interesting to note, Team Silent was pretty much split between SH3 and SH4, since they were developed almost simultaniously (actually Imamura and Tsuboyama were in pre-production phase of 'Room 302' while SH3 was in full development, but that's just technicalities
). It makes me hope the team is once again whole, with (as it seems now) plenty of development time for the next gen. Silent Hill 5.
Welcome to the series of Silent Hill. It's really in a league of it's own in the game world.