1989 - Unfortunately my neighborhood didn't get cable until 1989 so I missed the Superstation shows in the mid-80's and I've seen various things on tape and DVD but the year where I really got into it was 1989 because of Terry Funk.  His attack on Ric Flair after the Steamboat match where he gave Flair a piledriver on the table was great.  Then the first promo he did the week after that was just classic!  I cheered for Funk all summer because he was just so awesome and so different than anything I'd ever seen on WWF wrestling which was the only local TV we got in the 80's.  The I Quit Match that they had to end the feud is still the best match I've ever seen.
 
1989 also had the great Robin Green with Missy Hyatte both managing the Steiners angle.  One tripped Scott Steiner but Scott said it wad Robin and Rick said it was Missy because he was dating Robin, who turned out to be Woman.  She then brought Doom into the promotion to destroy The Steiners.  Her transformation from Robin Green into Woman was incredible because sje looked so plain as Robim but looked amazing as Woman.
 
There was also Muta vs. Sting that summer and Terry Gordy feuding with Dr. Death Steve Williams which was stiff!  They beat the hell out of each other.
 
There was also the introduction of The Skyscrapers- Sid Vicious and Dan Spivey.  They feuded with The Road Warriors.  Later Vicious got hurt and they replaced him with a very young Mark Calaway, called "Mean Mark."
 
Then of course there was the great series of matches with Steamboat and Flair earlier that year too.
 
In the best part of his career probably Lex Luger feuded with Steamboat that summer and actually cut some very goof promos on Steamboat when Luger turned heel.  Somehow he even got away with saying  something in a promo on The Superstation that I don't know how it avoided being censored  He got so mad he called Terry Funk "Terry F**k"!
 
They had a Great American Bash that summer with a Wargames too!

I'd have to say 1986. That entire year was just awesome. 1985 was pretty darn good, too.

Quote from slingshotsuplex on Jun 4^th, 2009, 7:10pm:

 
every one from the minute i started watching in or around the mid 70s.
 
EVERY one of em.

Mine would be 1976. Flair vs. Wahoo feud lasted the whole year, plus Blackjack Mulligan vs. Paul Jones for the US title, Anderson Brothers dominating as tag champs and finally upset by their cousin Ric Flair and Greg Valentine at the end of the year; the Anderson's feuds with Rufus R. Jones (the cap) and Wahoo (the cast). The trio of Mulligan, Flair, and Mosca in the fall of that year, like an early version of the Horsemen. The heel vs. heel NWA vs. IWA tag team feud between the Andersons and the Mongols. The debut of the Masked Superstar with Boris Malenko. It was just a magic year.  
 
My 2nd favorite year, or at least part of that year, was 10 years later - 1986 - that amazing four month period of May-August: The James Boys vs. The Midnight Express and the near lynching of Jim Cornette, the Tully Blanchard vs. Ronnie Garvin feud with the taped fists and the roll of quarters, the return of Ole Anderson and the return of the Four Horsemen to full strength; the Magnum TA vs. Nikita Koloff best of seven series; the Andersons vs. Rock and Roll Express feud all summer (I liked their matches together better than R&R vs. Midnight, I know that's blasphemous to some), the Rhodes/Flair NWA title switches along the Greensboro – Kansas City – St. Louis axis, and the out of nowhere heel turn on Dusty at that amazing August TV taping in Charlotte, one of the most heated crowds I’ve ever seen.

1985, 1986, 1987, and 1988. 85 was really good, 86 was awesome, 87 was good but not as good as 85 or 86, and 1988 had a lot of good stuff but unfortunately they sold out to Turner.

83 or 85 for me