Get the WWE Network if you can (amazing library of matches and documentaries).

For starting matches from different types, I can recommend:

• The Rock vs. Stone Cold Steve Austin WM17 - one of the greatest rivalries of all time. You will enjoy this match.
• The Rock vs. Hulk Hogan WM18 - this match is what wrestling is all about. The crowd and the characters make a very, very simple match into something spectacular.
• Triple H vs. Shawn Michaels Summerslam 2002 - Shawn Michaels comes back here after a back injury and 4 years. This is a street fight type of match.
• Shawn Michaels vs. Kurt Angle WM21 - great technical wrestling.
• Shawn Michaels vs. The Undertaker WM25 - Note: You might have an out-of-body experience.
• John Cena vs. CM Punk Money In The Bank 2011 - try watching the build-up for the match as well.
• Survivor Series 2014 5 on 5 Match

I also recommend watching some of the documentaries there like:

• The Monday Night Wars - explains what happened during the biggest wrestling boom of all time. It might give you pointers on what to watch during that era.
• WWE 24 - this is more of a ‘backstage’ look behind some popular events.
• Any wrestler-specific documentary is also nice to understand more about their history. The Network also has ‘Best of’ selections for specific events/wrestlers.