Some of these lists....
Ok I'll give it a go
1) AO 2012 - Djokovic vs Nadal (clear #1 for me and would be for every serious sportswriter if they combined a list. It had everything: quality, drama, longest Slam final in history, epic peak to peak gladiator battle, and the fact that it was a final made it even more noteworthy.)
2) AO 2005 - Safin vs Federer (not as good in quality as #1 but an epic battle nonetheless which decided the winner of this Slam. Safin taking on peak Federer and beating him in one of these best 5th sets I've seen when nobody else could touch him on hardcourt makes this one stand out for me.)
3) AO 2013 - Djokovic vs Wawrinka (quality at its peak is probably #1 but Djokovic wasn't great in the 1st set and a half so it brings it down. Still a very quality 4th round clash that we will never forget.)
4) AO 2009 - Nadal vs Verdasco (epic match quality wise and brutal hitting from Verdasco for 90% of the match and epic countering and defense to offense from Nadal.)
5) AO 2009 - Nadal vs Federer (brought down by a rather anticlimatic 5th set but doesn't deter from the intensity in the middle of the match. One of the most memorable AO finals)
6) AO 2003 - Roddick vs El Aynaoui (one of the best 5 set matches from the previous era and a 5 hour classic)
7) AO 2004 - Safin vs Agassi (one of Agassi's best matches later in his career and a great effort from Safin. Too bad he didn't bring that performance in the final)
8) AO 2017 - Nadal vs Federer (quality is not as great as the others and probably last or close to it in quality out of all of Fedal's 5 set matches, but the importance of it puts it on my list since it shaped the outlook of the Slam race, and it was their 1st Slam final in 6 years)
9) AO 2000 - Agassi vs Sampras (one of the best matches I've ever seen these two play in a Slam and you had to watch it in real time to really get the impact of it. Sampras all but had this one before Agassi turned this match on its head late in the 4th)
10 AO 2008 - Federer vs Tipsarevic (very underrated classic between Federer and his somewhat unknown challenger at the time. Some of the hitting in this was pretty insane, and one of the few times Federer hit 40 aces (39 actually but close enough)).