Armada-online
Top-down 3D space game ported from the Dreamcast version if im not mistaken.
I think this game was posted a few years back on some thread in the forum, thought i'd mention it since it's not in the list and is free, oh and it is still in a somewhat alpha version runs acceptably on 5year low end machines with the visual fx turned off and typing /texturedetail as well but it will still slow down in heavy screen action due to the excessive alpha texture blending pushing weak hardware like in my case a laptop IGP chipset. Last report from one dev said the animation and hit system was being re-worked, maybe that will improve performance a little, recent machines will have no problem whatsoever with this game, and you can increase the default resolution by typing for ex. /resolution 1280x1024
I personally think the game in its current state becomes boring after a 1 hour or 2 even with a decent group of players, the game suffer from heavy grinding and upgrading your ships will not be possible just by reaching a certain level wich makes things worse, u will need certain items, some wich u will find yourself others you will have to trade with luck you might get some for free from higher lvl players wich happens occasionally on the first ship upgrade possible at lvl 10.
Anyway it deserves a try, allot of the gameplay mechanics and areas are still missing but its somewhat promising specially if you are bored of constant fantasy mmo/rpg's out there.
Tips: don't play in solo, warp to delta3 and join the biggest group of ship/players u can find.
P - shows a list of players in the current instance/room.
Z - shows a map of the galaxy and its sectors by color each with a few specific types of things to hunt.
M - shows u a list of objectives depending on what area you are in.
NumLock - usefull later on in case u want to lead a group of followers, it will move your ship foward untill you Rclick in space or turn it off.
*edit: for more tips just press f1
Usefull websites with help/tips/info:
ArmadaHQ (wiki) some of its information is outdated, basics and most stuff is correct
ArmadaOnline Usefull to see the current different ships in the game, its systems and other charateristics in detail at different system levels.