I got hooked on that game like none other... I still run a tekkit server, though it's currently been dead since August. People will probably come back in a few months, usually happens in cycles.
Single player it's very boring, but multiplayer is awesome... collaborative builds are a blast.
This was the capitol of the server, Emain Macha, early on (Facing west):

6 months or so later (Same shot, but higher up and facing southwest):

That's not even 5% of the city itself, that's just part of the stuff I made, you can buy and sell things in the market there (by the big tree).
Then I added the floating fortress over it:

And

A smidge of the exterior of something I build long ago and imported (That's a TIE/IN on the pad, and a Viper in the hangar

)

Then the testament to my nerd digital lego fixation... a 1:10 scale ISD:

And inside:

The map is here:
http://www.80hd.net:8123/Server is just
www.80hd.netAll AH'rs are free to join... if a mod is on, tell them Tunnelrat cleared you, or PM me on here and I will give you build permissions.
You will need the Tekkit client to play (it adds about 10,000 new things to build... like nuclear reactors and such)