One of the old classic 4X space games was VGA Planets and it had a pretty big following in the day - the day being back when Ataris roamed the earth and the next generation of Star Trek was but a glimmer in Gene's eye.
It's Still going on. In fact there is a pretty interesting web site called Planets Nu which is a VGA Planets collector and which has a pretty good interface for HTML only. I'm telling you it's a lot like Space Empires in many ways which is giving it highest praise indeed. There seems to be a fairly active community and you can play some trial games for free. If you like it you can upgrade to the full monty for something like 30$ a year which is peanuts really for a decent game.
If you want to join up use my link so we can both get a 20% bonus on premium days. Premium days let you run extra games and stuff. I'm not sure what I'd do with premium days but there you go - its free stuff.