The first is Pharaoh, one of those isometric city-building games. It was my very first pc game back in 1999 and I remember loving playing it. All those tiny people running around and trying to please me...well, until I forgot to throw parties and the gods got angry. Oops.
The second one is Technomage, a German developed role-playing video game but even back then I played both versions (German and English) because it helped me to learn to speak English (at least that's what I told my mom). The different worlds are really beautiful, even though they're not as HD as these days, and the quests are sometimes not as easy to solve as you would think at first. :D
My favourite though is and always will be Arcanum: Of Steamworks and Magick Obscura, also a role-playing video game with an incredible open game world that I haven't managed to see all of it yet. I love the whole world layout and you can literally get lost in it and forget about your main quest. You have the choice between good and bad decision, and you never know how it's going to effect your journey until much later (when you're so bad that no ones wants to speak to you, you're screwed. Damn. I did better the second time around...) It's an amazing game. xD