I see Ultima VII was mentioned. Loved that game. Really, the whole Ultima series was great. I remember VII the most, though - since I played it as a kid on my older brother's lap. He had this huge map he had drawn of the world with all the locations marked haha.
Ultima VI can be played in Dosbox just fine, since it's turn based. I replayed VI, VII part 1 and 2, and VIII a few years ago. I played U6 in Dosbox, U7 using the Exult remake, and U8 I think I played on vdmsound? Been a while. I have the whole collection on a CD, as well as old floppies for some of the individual ones.
Ultima V and VI were also both remade using the dungeon siege engine - VI is still in beta, but very playable. They're at u5lazarus.com and u6project.com. I bought DS just for those remakes, but it was worth it
I also see Outpost and Outpost 2 mentioned. Great games. I still have my Outpost 2 CD, but I never could find another copy of Outpost 1 after I lost mine many years ago.
Lords of the Realm is another good one, as well as Lords of the Realm II. When I was a kid I played II online with some friends - fun game. Lords of Magic is somewhat similar with a fantasy setting, I played it a lot online too.
Oh, and *someone's* avatar just reminded me of another great game. Full Throttle.
I played that game to death. I loved the area where you used the little bunnies on the mine field, and later in the game where you could toss the bunnies into the car's fan and hear them get chopped up. (-edit- I should probably mention that they were little battery operated bunnies, not real bunnies, else someone mistake the game for some kind of sadistic simulator).