In your opinion, what is the best game you have played?
Don't consider graphics level. Just plot, fun factor, and replayability..
The game I liked the most was Starcontrol II. It's quite old (around 13 years old), but it was good. It was a "RPG" with some strategy and mysteries to be solved... I liked it.
The plot was quite intriguing...
In the sector map, you had around 100 systems to explore, with around 7 planets per system, some of them with up to 4 moons..
Around 14 races (7 per side), each one with a [very] different ship that you can fly. (at the point that a strategy you use with one ship is useless with another).
For today's standards it's not that good (graphics are terrible compared to today's games, and IA is a little dumb), but the concept and the plot was awesome...
The source code was set free in 2002. Actually there is a new version called "The ur-quan masters" that can run on actual PC's. And a SC 2.5 being made by fans (i've read the argument, it is quite good). (The SC III, the sequel, was quite bad)...
EDIT: replaced "argument" with "plot"
Edit2: corrected the terrible grammar. Thanks to Osorojo for pointing out the mistakes.
(If you find any mistake in my English, please let me know via a PM)
(Really, I speak terrible English, so please, tell me if I make mistakes. I'd like to improve it a bit )