Ultima 7 is considered by some to be the best version of the Ultima series of games created by Richard Garriott and even considered to be one of the best RPG's ever due it's scale and complexity.

Exult is a great way to allow you to play the game in all it's glory on modern computers. The only downside is you will need the original data files to be able to play but you may be able to find the game on Ebay.

Recent developments of Exult will allow you to make custom maps and scenarios so expect user made mods.

There are version of Exult for various systems. As well as Linux, OS X and Windows there are various handheld versions for systems like the GP32 and GP2x and Zaurus.