The game I'm currently playing would be my largest empire.
Planets: 102
Total Ships: 495 (this includes numerous construction ships, so thus number varies)
Attack Ships: 267
Transports: 107 (I like to be prepared)
Starbases: 51
This Sandbox game has been rather boring aside from the numerous wars the other races get into. The Jagged Knife haven't struck yet, neither have the Peacekeepers or Dreadlords, and the Pirate Invasion spawned only ONE ship. As such, it's allowed me to just build up and fortify rather peacefully.
As for strategy, mine's pretty much the same. I love a technological advantage.