That's a tough one. Different people have different favorites. But for many, 'The Avengers' series is highly regarded for its epic storylines and diverse characters.
I think 'Darth Vader: Dark Lord of the Sith' is one of the best. It's so cool to see Vader's early journey as a Sith. His relationship with Palpatine is really well - explored. Another great one is 'Kanan: The Last Padawan'. It tells a touching story about Kanan's growth as a Jedi in a difficult time. And 'Chewbacca' is also a great story. It shows Chewie's own adventures, which are different from what we usually see when he's with Han Solo.
I'd say 'Whatever Happened to the Man of Tomorrow?' is a great one. It was sort of a farewell story for the Silver Age Superman. It has a lot of mystery and nostalgia. It ties up a lot of loose ends and has some really cool and creative moments that are true to the character's long - standing history.
The 'Infinity Gauntlet' storyline is hard to beat. Thanos' quest to gather all the Infinity Stones and his snap that wipes out half of all life in the universe is a huge and epic story that has had a major impact on the Marvel universe both in comics and in the movies.
It's hard to pick just one, but 'Xenomorph: Invasion' is often considered a top choice due to its engaging plot and well-developed characters. It offers a fresh take on the xenomorph mythos.
It really depends on your personal preferences. Some might love superhero stories for the action and adventure, while others might prefer slice-of-life comics for their relatability.