Need games to play for a loooooong time.

You should play Oblivion for Shivering Isles. It's one of the best RPG stories ever told and graphics fit way better here.

Well if you like rogue-likes, there's always ToME (aka Tales/Troubles of Middle Earth). It's what eventually spawned Tales of Maj'Eyal, though in my opinion it's a lot more fun. I've played it since...what, 2003? Earlier? I've never beat it, but I have a ton of characters and it's just loads of fun. Here is a mirror for the last version developed by the creator DarkGod, while here is a version I just found being updated by the community.

There's ToMENet too, a multiplayer version. I can't say too much about it though since I only played it once and I just realized it was still running.

In any case, prepare to die. A lot. I believe the community called such instances YASD or YASDing for Yet Another Stupid Death, which you WILL have happen.

Don't forget to turn on graphics, since it's otherwise a character-based rogue-like.

Enjoy! :)

Lord of the Rings Online. Mount and Blade games, or probably Chivalry Medieval Warfare. Also, play Star Wars Knights of the Old Republic 1 and 2, those are nice to spend hours. Not medieval, but the story and gameplay are awesome.

"Fallout: FPS not my thing :( Maybe I'll get into it, I dunno. Or maybe I should play the "demo"... And then buy it if I liked it."
Off with my hat. I also started out as a pirate, but some games really deserve to be owned and give feedback with your purchase that you love the way they are faring. Also, good that you want to try it out before buying it and this way avoiding unwanted surprises :)

Witcher 1 & 2
Mount & Blade

Want something endless and to relax? Euro Truck Simulator 2. Just test it and you will see.

If you go for Civ, get V + all DLC.

RPGs do you prefer? Why not all Witcher games and/or KOTOR games?

If turn based strategy is your thing, "The Battle for Wesnoth" is a great game that will keep you up and going for hours.
IT's FREE ;)

I have been killing so much time in Path of Exile. Great free ARPG.

Dota I guess.

If you're up for skyrim,I don't know what you mean by cartoonish - perhaps you need higher resolution packs,but for being too bright,you can try something like the Bleak ENB,Blackout or Darker Nights (and there are others,if you just search). Too happy?.. Perhaps something like a combination of Deadly Mutilations and Crimson Tide,maybe throw in Immersive FPV.

try Final fantasy VII or VIII