I'm still on my Master of Orion kick. After stomping on everyone in a Normal game i tried Hard, and lost almost immediately. I went back to Sulla's MoO game logs and read through a bunch of them, plus an educational succession game on CivFanatics and picked up a lot of tips.
After that i was suddenly able to finish Hard games in Ironman style on a pretty regular basis. In fact i found that if i reduce the map size to Medium i could often knock one out in about three hours.
I finally decided i should try moving up to Impossibly difficulty, though i stuck with the Medium map size. (I'm really not sure how well map size affects difficulty. I guess in theory if you're expanding well you ought to be able to take better advantage of a Large map than the AI would, and if you're not expanding well you'll probably get creamed.)
To make things easier on myself i played as the Psilons, considered to be by far the easiest race in the game, though i think a reasonable argument could be made for the Klackons as well.
In any case i got off to a fairly good start and got most of a corner to myself. That put me in a reasonably strong position, but definitely not enough to dominate. It wasn't long before the race that got something like 1/2 or 2/3rds of the north part of the map (Meklars i think?) started out-teching and out-building me. (Kind of an embarrassing situation to be in for the Psilons)
Then sometime around the second or third election, pretty much right off the bat, everyone decided to vote for the Meklars and i lost the game, which is even more embarrassing =P So i cheated a bit and continued the game (It automatically keeps a "latest save" which doesn't get overwritten if you lose the election since that technically happens between turns) and bribed a couple people and convinced them to abstain or vote for me instead, so i was able to continue on with the game, but it was no longer Ironman.
Pretty soon after that they started "visiting" my colony worlds. At this point they should have started kicking my ass, but they did something a little odd. They picked just one world to pick on at first. A large fleet would visit and knock my missile bases down to about 15-20. Then they would retreat. I would spend a couple turns frantically rebuilding missile bases and then the enemy would come back. Wash, rinse, repeat.
They did eventually take over the colony, but i gained a fair bit of time because of their hesitancy. When they picked a second colony to focus on i had even better defenses, and they repeated the same behviour. Eventually i was able to get to the point where i could build teleporting bombers which i was able to send on a tour of destruction through the enemy worlds.
If they'd just stuck with their attacks instead of retreating so often they probably could have crushed me. Even more so if they'd started wiping out some of my weaker planets instead of continuously focusing on a planet without defeating it, giving me time to focus all my defensive efforts there.
Of course it's because of things like that that the AI is given such a huge advantage on the higher difficulty levels to begin with :)