Tintin is the first that comes to my mind. I remember my Grandfather telling "Tintin Milou" instead of "Tintin AND Milou" (Snowy). It was probably the only comic he ever read, but that was a piece of culture he revered.
My favourite Tintin album must be Destination Moon and Explorers on the Moon. It's crazy to think they were published in 1953 and 1954, less than 10 years after the end of the war. The V2 inspired rocket is so iconic.
The next character I have to evoke is Astérix, it felt easier to read than Tintin but that was deceptive. Asterix is satire, and that satire is best appreciated if you are more advanced in age.
My favourite Astérix album must be Asterix and Cleopatra, I think I received it from my mother on some winter day, I can't remember exactly. I was into Lego at the time and the palace building exposed in the album talked to me.
One thing I did not like about Astérix is how ahistorical it is. Remove the "stér" and replace it with an "l" and you get Alix. Those two comics share Julius Caeasar as a character, but Alix is much more historical.
The first Alix album I had in my hands was "Alix l'intrépide", but my favourite album was "The Lost Legions". It featured a plot detected in Italy and a race between Rome and central Gaul to prevent a set of legions to run into a trap. Years later I read in De Bello Gallico the episodes it builds on and I loved them.
The next serie I have to mention is Blake and Mortimer. I only read it seriously when I was around 25. When I was younger I didn't own any of those albums, they were on the shelves of the older brother of a friend and they looked intimidating.
The serie has a fading British Empire feeling which is endearing. The technology is fun. At times, reading at 25, I felt an invasion of this setting by Lovecraftian lore might be excellent fun.
I loved Yoko Tsuno, it is full of technology and cool looking flying things. One thing I particularly liked is that those things came in various versions. The space ships had extensions to give them special propulsion systems for certain travels. I built a lot of Lego space ships based on those albums.
Gaston is very different, he's a goofy office worker whose colleagues try to prevent from sabotaging the company's operations. An album is a serie of short jokes, many of them featuring interesting contraptions Gaston builds to avoid working, to play music, to avoid paying parking fees for his car...
My uncle was a Gaston fan and he sometimes let me read some albums. Restricted access made it even better.
I only read a few Thorgal, but I plan to read it all in the coming years, especially since I lead a campaign between Britannia and Scandinavia.
Why didn't I read Thorgal sooner? Maybe because I was reading the Hobbit and the Lord of the Rings, and Asimov...
I did not read American comics, I was not interested and had only access to Scrooge McDuck and friends.
I wish the Franco-Belgian comic school will go on in the coming years, but the opposition, the combination of American and Japanese soft power, riding the net, might wreck it. Television kills accents and dialects. What will the net kill?