Might & Magic is good, I also really like Wizardry. If you wanna look at "Gold Box" games, the old D&D crpgs, I'd recommend starting with like Champions of Krynn as it's considerably less difficult than say Pool of Radiance or something. There is of course Ultima, though the first two are very different than the next 3 but that's not a bad thing. If you're a fan of Fallout you could also check out Wasteland, the game those teams first worked on. Those are really the big "mainstream" ones, and any of them would be an excellent place to start. You're going to want to make sure you have some form of the game manual for each of them though, as they make heavy use of shortcuts on the keyboard and a lot of the descriptions aren't actually in the games. For added fun, you can also keep some graph paper handy and draw out your dungeons as you play, as a lot of them don't include a map.
