I think it really depends on what the OP likes ultimately.
If you want brilliantly created and detailed worlds with very nicely written characters that you can lose yourself in then I think The Stand / IT are good suggestions. Possibly Talisman / Black House in there too but they aren’t solo SK efforts.
There are some excellent collections of short stories if you want a quicker fix.
I’d agree that there is some ‘shlock’ in his catalogue – Pet Semetary potentially falling into that.
I actually found Under the Dome very disappointing in terms of the ending but it is another example of how well he can build a believable world for the reader.
Also – do you want overtly scary or more thoughtful / considered frights?
I guess I’d also say hold off the Dark Tower until you read a few others. It is an extraordinary series for me both in content and in terms of how interwoven it is / many other books are to it (depending on your POV). I say ‘I guess’ because I love it and want to share it with people but you do get more from it if you read others first. There is a site somewhere that will tell you which books to read when if you’re just starting the DT series (8 books now and 1 short story – The Little Sisters of Eluria although only the first 7 are ‘key’ ;D).