Kind of what I figured, I never read any of them consistently, I'd usually grab the one with a favorite villain!

When we had PPSSM, ASM and MTU, they were quite different and run independently to a large degree. PPSSM and ASM had some ties (Hobgoblin, Felicia, Foolkiller, Vulture...) around the time Stern made the switch from one title to the other. Once he left, they regained part of the lost autonomy. MTU was pretty much self-contained, that changed when the title was transformed into WOSM, supporting characters started appearing there too.
In general, PPSSM was focused on Peter's campus life, and ASM on his photographer career.

Welcome to the forum Snikts and Stones!

As primarily a Spidey fan, I felt obligated to chime in with what little I know, in hopes of persuading you to read some of the classic issues!

Amazing Spider-Man is the original and best in my opinion. The first 100 issues feature the best classic artwork from Ditko and Romita and all of the classic villains. Great stuff and worth finding in any form to read. From issue 101-150, you get the classic Death of Gwen Stacy, a great Goblin story and the original clone saga which I love. From #151-200, nothing groundbreaking but still good artwork. #200-237 are also good but nothing spectacular, with the exception of a few individual issues. #238 introduces Hobgoblin and his involvement carries the stories until about #289. It is a good run, even if the ending was not what was originally planned. From #290-328 you have the classic Kraven's Last Hunt and then at #297, the artwork is taken over by Todd McFarlane and the introduction of Venom takes charge. After McFarlane leaves, the artwork is primarily taken over by Erik Larsen who does a good job of keep his style. The stories are average up until #365. At this point, Peter's parents are brought into the fold and the stories are not as great up until #400, which is a solid story. At this point, the series enters the 90's and loses a lot of appeal for me personally.

If you want to collect single issues of a Spidey series on the cheap with good artwork and simply storylines, Peter Parker the Spectacular Spider-Man is where it is at! The first 100 issues are just good fun, with great covers and some oddball characters at times. They do focus more around Peter and his friends (when not focusing on Spidey fighting). There are not many great storylines but again, for pick up and go reading, it is the simplest in my opinion. After #100, the story features police captain Jean DeWolff and the Sin Eater and it is a pretty good story arc (starts around #105 and ends around #119 if memory serves). The series is then just good fun, with solid artwork by Buscema up until #200. This is when the series enters the 90s and my knowledge fades. Once again, the second clone saga really twists up the Marvel world in a way that I never liked. But as a whole, this series is good plus, very cheap to find these issues.

Marvel Team-Up featured Spidey teaming up with everyone imaginable. Once again, great artwork and good fun simple stories. The first 60 are my favourite. After that, the team-up stories are not as strong or as fun but it is still a good series if you like seeing Spider-Man alongside others. Generally, the storylines lasted 2 issues at most, so they are easy to pick up and read.

Spidey Super Stories did not tie in (to my knowledge) with any series. It was published in connection with the Electric Company and had some great artwork but the stories were geared for kids so the writing is very simplistic. Still, a more obscure title that is harder to track down and likely has a lot of Spidey adventures that many comic fans have never read.

Finally, Web of Spider-Man is my least favourite. With the exception of a small handful of issues (like the tie in with Kraven's Last Hunt), I find the stories sub par. The artwork, especially the covers, also leaves a lot to be desired. As far as original Spidey titles, I have the least love for this series.

That is the extent of my Spidey knowledge. As mentioned, the 90s ruined the character for me. I read a few later titles like Sensational Spider-Man and Peter Parker, Spider-Man. At this point, there were too many titles to keep track of and having missed 1994-1998, I felt out of the loop. I stayed away from newer comics through my youth and focused on collecting the old stuff. To this day, I have not ventured back into Spider-Man because no one has come forth and said "you have to read this!". I also find the artwork lacking in general...maybe someday I will but for now, Spider-Man lives from 1963-1993 in my mind.

^ I enjoyed Carrion a lot. Always loved the way he was drawn and when he and Hobgoblin met up in Spec Spidey, I loved that little arc.

#224-251 contain most of the best SM stories ever.

It didn't tie in with other titles, because it isn't part of the earth-616 continuity. It's set on Earth-57780.

Call me "no one", you have to read ASM #471-476, 478-479, 484-491, 506-508, 532-543.

For alternative picks, the OP can check my individual ratings, for every SM comic from the 60's trough the 80's (up to December '89). Based on your previous opinion, about the ones you've actually read, you'll be able to see which recommendation makes more sense to you.

From #66 to #72, I find 5 of the best 23 comics, out of the first 157 issues (the classic era).