For those wishing for a sequel to Freespace 2, well it won't happen, but here is the next best thing.
The Freespace source code project.We will probably never get an official Freespace 3, but that doesn't matter. With the SCP it looks as badass as any modern game and has all the sweet gameplay and more features than retail ever had. It plays on all three mainstream OS's found on a x86.
It is little fiddly on first install unless you find and use a torrent with everything prearranged. Once you get everything working, it's not Nintendo solid, but it would slap a 360 silly.
It's not entirely free in the sense that the installer on the site is missing some retail files you need to run, but copies can be purchased from GOG for a pretty reasonable price. Once you are done replaying the retail campaigns, have gander at the user made.
Blue Planet: Age of Aquarius - Director's Cut Is so good, it might as well be Freespace 3. Set after the events of FS2, so play retail first. It's a little heavy on philosophy and mysticism but packs some serious gameplay. It's sequel just released,
War in Heaven, eases off on the religion and is a more personal story. It has a lot more boom than AOA. It's not yet fully voice acted like AOA, but that is in the works.
There are also a bunch of really good campaigns that come with the installer. Joystick or equivalent is very highly recommended. Have fun.