1-3 are fantastic, unless I missed it I don't think anyone's commented on 2 having a fantastic soundtrack (subjectively one of my fave game soundtracks of all time). SH1 actually has a dark, more violent tone and story in my opinion and is very scary because of how dark and sprawling the world is. SH2 just looks amazing and still holds up so well visually, gameplay just a bit bleh. I think you need to play SH1 to truly appreciate the story of SH3; it's a great game too but the story is perhaps more convoluted than 1 and 2 while also not being particularly interesting to me. Also, SH3 marked the beginning of them trying to add more "combat" to the series and so you end up fighting alot more enemies in 3 which is very much not the strong suit of the series; this makes for a more laborious play through experience if you ask me compared to 1-2.
I'm happy to join the chorus of folks saying to play 1-3, with SH2 taking the cake for a variety of reasons personally.