I own both Dom2 and Dom3 and am generally a big fan of the series. It has just the right balance between the epic feel (world-wide rituals, huge armies, summoning, eras, number of players...) and heroism (leaders can be equipped with self-forged weapons, armour, trinkets..., assassins, spies...).
The interface isn't the best ever, granted, but you have to give several bonus points for running natively on windows (incl. vista), linux, mac, solaris... pretty much any OS you can think of. Without needing a VM! And users of different OS can play in the same game, it features a command-line server component for processing turns, meaning you can have a server running 24/7, players doing their turns and once all turns are in, the server generates the next turn. Then each player can login, play their turn, etc.
To be honest, the game is more for MP than SP, as the AI is a bit lacking. Still, great fun and one of the first games I install on a new computer. Also, no CD-check once your key is entered.
The demo only scratches the surface with it's turn limit and research up to level four. On smaller maps, that's ok, but usually that's when thing only start to get interesting. While we're on the subject of maps: There are high quality pre-made ones, you can easily import your own, randomly generate one or generate one and then tweak it with an easy to use interface to your liking.
Really, the only drawback is the interface, but you get used to it pretty quickly. If you're looking for a good indie game to fill your fantasy TBS craving, look no further than Dom3.
