Top 5 in chronological order (My list is basically from 2000 forward, since those are the shows I really know).
2006: Machine was the show that got me into drum corps when I caught it on ESPN. Nothing more to say that's already been said, other than that there is a reason it makes up half of my username.
2007: And So It Goes is such an underrated show, being sandwiched between 06 and 08, but Billy Joel is such a great soundtrack for the field. Amazing music, fun visuals, this show just rocks!
2008: Samurai was just stunning. Machine introduced me, Samurai made me fall in love. Still my all time favorite drum break, and it's going to take a lot to change that.
2010: Mad World was the first show I saw rehearsed live (I'm still mad at Mother Nature for raining out the Lisle contest!), and... Wow. I never marched, but this show made me consider talking to my college band teacher and asking him if I could borrow a mello to practice for 2011. Just seeing the dedication to their craft without the performance lights shining, seeing the raw energy and emotion... I think someone already said this, but this show is the defining LOS show for me. This is the show I show people to introduce them to DCI. Mad World will always have a spot in my heart, right behind Faust for pre-LOS.
2016: Propaganda was what this corps needed and what cemented what will be a very successful future for the corps. It's such an intense, fun, and appealing show. Super easy to get into. Super proud as a fan of this corps to see this follow 2015.
2002: Yes, I'm the odd one out who doesn't really like Frameworks. I used to love this show, but after a while, I just got bored with it. I just skip to the drum break to the end when I watch it now. I really hope I refind the spark I had with this show.
2013: I love the music, and the idea of Secret Society. It just doesn't click with me.
2015: Game On was a sketchy show for me from the beginning, and I feel like this was a huge swing and miss for what they could've done with the theme.