The Escape Velocity games are fantastic, and unfortunately very little known among Windows users. My friend who was a Mac guy introduced me too it. The third game in the series finally got a Windows port, you can get the demo here: http://www.ambrosiasw.com/games/evn/
The demo is exactly as the full version, only you cannot board enemy ships after damaging them and steal their cargo. Also after a few days of playing the demo a ship will come on screen, tell you to register then blow you up, this makes the game very difficult to play, but you will have a couple of weeks to play without this happening.
To slip back on topic, I bet this game doesn't work on Vista.