Expect a lot of 'tards to give you sh*t for being a UFC fan, though. Quite frankly, the striking in MMA is an embarassment.
As for fights to check out - There's a wealth of them on youtube that should suffice. You also can't go wrong with boxing documentaries and mini-series like 'Legendary Nights'
Obviously this sport has a colossal history of epic rivalries that you should check out : Stuff like the trilogies between Ali and Frazier, Bowe and Holyfield, Barrera and Morales, Vazquez and Marquez, Marquez and Pacquiao, Ward and Gatti, Duran and Leonard (though the third was kind of a farce), Pacquiao and Morales, Gonzalez and Carbajal, Ali and Norton, Duran and DeJesus - The list goes on and on.
Then there are single fights that over the course of 12 or 15 rounds became the stuff legends are made of : Stuff like Corrales vs Castillo 1, Hagler vs Hearns, Leonard vs Hearns 1, Chavez vs Taylor 1, Dempsey vs. Firpo, Louis vs. Conn, Lewis vs. Klitschko, Pryor vs. Arguello, again this is a seemingly endless list.
That should be more than enough material to cement anybody's love of this sport, but there are plenty of other amazing fights out there and new ones being fought nearly every weekend, so you've got a lot of watching to do.
Thankfully, it'll be the most entertaining homework project you've ever had.