Freespace 2 was the definitive in-cockpit ship-to-ship space combat simulator of the transitionary period between the 90's and 2000's. If you have any interest in this genre, and you haven't played this game yet, you're missing out on the masterstroke that paved the way for games like Freelancer and EVE Online.
If you're having technical issues be sure to check out the Freespace Open project, which attempts to fix some of the bugs and update the graphics and lighting to a level contemporary players may be more comfortable with. For me personally, as-downloaded, my installation of Freespace 2 refused to run properly, but after installing FSO, it executes effortlessly.
In the space of a few minutes, you'll find yourself weaving between capital ships, trying to dodge flak, focus-fire on enemy capital weaponry to disarm them, and dog-fighting with customizable ships and loadouts. All the while, a grand narrative is unfolding with plenty of little twists and flavor to keep your interest.
Best of luck, pilots.