Well good luck finding JCP from the 70s. You MIGHT be able to find an hour of that if you spend half a day looking.
Here's what you should do if you want history:
WWF Mid 80s: Brawl to End It All, War to Settle the Score, Wrestlemania I
NWA early 80s: Starrcade 1983 (holds up VERY well) and Starrcade 1985 (possibly the best Starrcade ever produced)
NWA late 80s: Anything from 1989, but especially Flair vs. Steamboat from Chi-Town Rumble (look for the fan with big hair in a blue shirt across from the cameras. It's Dave Meltzer), Flair vs. Steamboat from Clash of the Champions 6, Flair vs. Steamboat from WrestleWar 89 (occasionally called the greatest match ever), all of Great American Bash 1989 (called the best WCW/NWA PPV of all time).
Late 80s WWF: Hulkamania Volume 3, although find the full versions of the matches instead of the clipped versions on the tape. It covers almost all of Hogan's run with the title up through the Mega Powers Exploding. The other required show from that era is WrestleMania 3 which also holds up remarkably well. Survivor Series 1987 is very good stuff as well and is basically Hogan vs. Andre 1.5.
There isn't much to see in the early 90s anywhere, although if you want a quick sample of each check out Wrestlemania X and Beach Blast 1992 (though watch the Sting vs. Cactus match last. The show is WAY better that way). Oh and check out WarGames from WrestleWar 1992 if you want to see an absolute bloodbath.
WCW after 96....be prepared to be disappointed. The problem with these shows is you kind of have to watch all of them in order to get why they're so awesome. It's all about the week to week drama rather than one big show. If you're looking for a great PPV from that era though, check out Souled Out 98 which is the follow up to the disaster that was Starrcade 97.
ECW.....I'm not a big fan at all but they definitely left their mark. I'd tell you to watch Rise and Fall of ECW and call it a day for them but if you want to see more, the best I can recommend to you is Barely Legal which holds up pretty well.
Attitude Era: definitely worth seeing, but stop after early 1999 because it drops through the floor in quality. PIck things up in early 2000 and watch everything you can from that year other than Wrestlemania 2000 and King of the Ring. Those shows SUCKED. Make sure you check out Royal Rumble 2000, No Way Out 2000 and Backlash 2000. They're all over a four month stretch and are probably 3 of the top 15-20 shows the company has ever produced with Backlash cracking the top 5 or so. As for individual matches: Bret vs. AUstin from WM 13, Austin vs. Dude Love from Over the Edge 98, Rock vs. HHH in a ladder match from Summerslam 98, anything of Rock vs. Mankind from early 1999. Also check out In Your House 16: Canadian Stampede. It's less than two hours and is one of the best shows of all time.
As for time after the Attitude Era, make sure to hit Summerslam 2002, Royal Rumble 2001, No Way Out 2001 and Wrestlemania X7, which is the greatest show of all time. Just make sure you get the original version and not the one with My Way dubbed out. The video package for the main event will give you chills.
I'm not sure if that's what you were shooting for but it should keep you busy for five weeks.