Sword of the Stars (and the expansion Born of Blood) are both very good.

Stars!

Excellent pick KuroTora.

Freeform 4x ( ie, no starlanes ) hasn't really been done since.

For the younger kids , catch yourself up on 4x history at the stars! wikipedia page:
http://en.wikipedia.org/wiki/Stars!

I loved Pax Imperia 2, I still play it on occasion. I know I played the hell out of IG2 also, but I haven't played it for years. I can't quite recall why I stopped, I think I was waiting for a patch that never came. I've played GalCiv2 quite a bit also, but I always end up playing the role of "ship designer" more than that of "emperor".

Star Trek: Birth of the Federation, is in my opinion the finest Space 4X game ever created. I have been dreaming of a sequel for years.

GalCiv 2 plus expansions, SotS: Born of Blood and Dominions 3.

@Zaisha


Hi Zaisha,
Read my reply #22 and instead install MS DOS then you might be able to play it

@Raging Amish


Really a fine game also. I have so many so I can easily forget mention some of them!! And one of these is Sword of the Stars . . . love this game also.

Redion

A lot of years ago (15?) I played a 4x game on a computer bulletin board system (bbs). This was before the internet got popular. You dialed a phone number with your computer/modem and logged on and played games, posted messages etc, then logged off. Well the 4x game was Esterian Conquest, a bbs "door" program or game. I played one turn per day with about 11 other people, otherwise it was very similar to Sins and other 4x games; build colony ships, fleets with frigates, cruisers, battleships and troop carriers. You took a world by destroying its defenses then invading it. We made and broke alliances and all that. Graphics were ascii text. It took us all of a year to play to the finish and it was fun!

WOW, someone else remembers all those old BBS games. If you want to go back that far, I remember playing a BBS version of RISK. That counts as 4X I think. You could make as many moves as you wanted per day, but you only got new armies once every 24 hours. I remember staying up until the wee hours of the night to play the game at 11 PM and replay it again at 1 AM. It was a great game for me. There is only one problem with RISK that I ever ran into, and this is true for the board game or any digital version, is the dice NEVER work for me. EVER. I remember claiming all of Africa (with reasonable defense) and I got stomped because I kept rolling 1's.

My ultimate favorite BBS game was Food Fight! Not 4x, but still my favorite.

I am glad someone else remembers the good ol BBS days. For you kiddies out there, that is when a Hayes 2400 baud modem ruled the world!

AD 1602 is the only other one I played. It was pretty awesome back in the day.

Alpha Centauri is my all time favorite. Followed by Master of Magic, and then probably Master of Orion 2. Also liked Civilization 2. Not quite as fond of 3 and 4. Oh, and of course, Galactic Civilizations 2 and Sins.

MOO3 will always be special to me since the GalCiv ad in the box led me here

Roadkill...I played a few bbs door games each day, on a couple different local bbses. There was Esterian Conquest, then the Risk type game and chess. Tradewars was available (kind of 4x plus rpg) but I never got that into it. The good old days, when you actually got to meet some of the people you played online with.