Ah yes, the storygames, I actually wish someone had asked me this question earlier; I was going to put my personal top five or ten on the "Your favorite storygames" thread, but it was several months old, and necroing of threads is usually frowned upon in most online communities, so I was like "meh."
Naturally, Eternal is one I absolutely adore (which shouldn't be surprising, since it's on virtually everyone's list ever), and it would easily land my Top 3 list. It's got to be Endmaster's magnum opus.
Dead Man Walking is another personal favorite. Possibly the single most expansive storygame on the site (one of Endmaster's may actually exceed it in length, but I've never seen an official page count for any of his stories, so I don't know).
Last, "Farewell, My Childhood Self" I absolutely loved. In my personal opinion, it's the best Romance story on the site. It had the perfect blend of melancholy and joy for me to not be overwhelmed either way.
All three of these earn a personal score of 8/8 (Best of the Best), for me.
Honourable mentions:
Snow: This would have overtook My Childhood Self if it wasn't so goddamn depressing. The end of the story actually elicited a tear from me... legit. But then, I suppose that's what it was going for. 7/8 (Amazing)
The Homo Perfectus series: What can I say, I LOVE superhero stuff, so an actual superhero themed storygame was brilliant to me. It has a good idea in how it handles the superpowers; the writing could definitely improve, however. 6/8 (Good)