If you like Rogue-likes then I would HIGHLY recommend Tales of Maj'Eyal for win/mac/linux. It's easily the best rogue-like I've ever played. As a bonus it's free and open source, and has tons of updates. It also has support for addons and custom modules using the open source engine.
www.te4.org
Even if you have no background with rogue-likes you should check it out. It's about the most well rounded classical rpg type rogue around.