I'm a big fan of the whole Dune universe. Although I'm into the novels more than anything (the preludes were great), the games have been above average. The original game published by Virgin (by Westwood?) was great for the time IMO. A good mix of strategy and adventuring. The Sega CD version has lots of speech, and the voice acting is... well... pretty good, in comparison to some of the more recent game efforts.
Emperor Battle for Dune (PC) is my favourite of the series, although I remember playing Dune II on PC and Megadrive an aweful lot.