Noy really a game site, but the amount of time that went into this, the backgrounds and the graphics make it definately worth a read. Deals alot with transitional technology from fusion missles to photon torpedoes, advancement in warp drive, and the switch from deuterium fusion to M/AM reactors. The parts on the Romulan War are very good as well as the halting development of the Klingon war machine. Great stuff.
The Lancaster, Constitution, and Yorktown/Minotaur entries were some of my favs.
http://www.starfleet-museum.org/index.htm