Here's some of my favorite animez, all of it devoid of the typical fan service type stuff. I'll group this around the directors/creators, because I think that's an interesting approach.
Leiji Matsumoto
The original master of space opera. Very unique style, distinctive character designs, with an almost gothic, late 19th century approach to space adventure. Matsumoto's heroes are wild, free, and ambitious, but they're held back by an Earth government that just wants to sit back and live in corrupt, idle luxury. You'll see a lot of the same character "types" appear in these stories: the shaggy-haired, stoic wanderer; his stout and ugly but genius companion; the mysterious beautiful woman; the wide-eyed, passionate kid who falls into the orbit of these larger than life heroes. There are a
bunch of Matsumoto projects that feature variations on these themes, and some of the stories can be considered alternate universes/timelines.
Check out: Galaxy Express 999 (fantasy sci-fi), Space Battleship Yamato (military sci-fi adventure), Captain Harlock (sci-fi action), Gun Frontier (Western), The Cockpit (World War II stories)
Noboru Ishiguro
Ishiguro mostly directed stories that were created by other people: Yamato for Matsumoto, discussed above; Macross for Shoji Kawamori; Legend of the Galactic Heroes from the novels by Yoshiki Tanaka. In all of these projects, Ishiguro brings a thoughtfulness and humanistic sensitivity that is rare in anime. He deals with science-fiction and war in a way that has a real human touch. He shows you the cost of war, and more than anything, you get a deep look into the personalities and emotions behind the people who fight in a war. This is especially evident in Legend of the Galactic Heroes, which is an absolutely
epic deep dive into the total human picture of armed conflict. You meet characters on both sides - grunt soldiers, officers, politicians, black market con artists, business people, social activists, religious cultists, regular folks on the street - and you get this panoramic view of war that I find very compelling. Very few, if any, of the characters are purely "good" or "bad" and everyone has their reasons.
Check out: Space Battleship Yamato (military sci-fi adventure), Super Dimensional Fortress Macross (sci-fi action/drama), Megazone 23 (cyberpunk action), Super Dimension Century Orguss (sci-fi action/drama), Legend of the Galactic Heroes (military sci-fi drama)
Yasuhiro Imagawa
Imagawa has had an interesting, unusual career: he's become famous for taking stories by old school artists and turning them into something fresh and new. For instance, in Giant Robo, Imagawa incorporated just about every story drawn by a mangaka from the 50s named Mitsuteru Yokoyama. Yokoyama was a contemporary of Tezuka, and he tried out just about every genre (and in some cases, created a few genres), so his work is really all over the place: ancient Chinese war stories, psychic powers, giant robots, magical girls, ninja adventure, etc. Imagawa managed to fit characters from all of these different stories into one super-epic pulp workout that just gets bigger and crazier over the course of its seven episodes. He applied a similar approach to Shin Mazinger Z, which adapts the Mazinger Z story but includes characters from other Go Nagai projects like Violence Jack, Abashiri Family, etc.
Check out: Giant Robo (mecha pulp adventure, based on the works of Mitsuteru Yokoyama), G Gundam (mecha action, basically Gundam meets Street Fighter), Tetsujin 28-go (mecha mystery drama, adaptation of the original stories by Mitsuteru Yokoyama), Shin Mazinger Z hen (mecha action, based on the works of Go Nagai)
I highly recommend all of these shows! In fact, next to the original Gundam, the material created by these three guys - in particular Giant Robo, Captain Harlock, Macross, and Legend of the Galactic Heroes - is my favorite anime stuff ever. If anyone knows anything else in this vein, I'd be happy to hear about it.