Originally released in 1994. I remember playing this game with my dad when I was a kid.
http://en.wikipedia.org/wiki/Master_of_magichttp://www.gog.com/en/gamecard/master_of_magic ($5.99 for an XP/Vista/7 compatible version)
Master of Magic is an old single-player strategy game that I love. The gameplay is like Civilization with wizards and magic, also similar to the Might and Magic series but more magic-oriented. It is purely single-player, though there is a mod available that allows hot-seat play with two players on the same computer.
The Civ-like elements are the city building, management of resources, and map play. The game is driven by magic though - you, as the wizard managing cities and controlling armies, choose from a mix of five types of magic (life, death, nature, chaos, sorcery) that can summon fantastic creatures, enchant units or cities, cast overland enchantments, and get involved in combat. There are countless customization options - you have 11 picks to choose spellbooks and abilities, plus a bunch of different races which each have some unique units and things they can build within cities. The gameplay is great, there are quite a few possibilities in both player customization (spells/magic types, different races for cities/units, and difficulty/world options) as well as how you play (you can focus on or balance magic, cities, armies, etc.)
There are a few stability issues that I have encountered that occasionally require restarting, but I haven't had any problems that caused me to lose save files, I can always restart at the beginning of the last turn. There are also mods and user-made patches/updates available.