I play normal, everything common-abundant, tech very fast. Typically, i buy 1 factory, build 1 morale, 2 more factories, 1 research, then after that i go on bonuses and what i need rigt now. Starports usually come fairly late (or nto at all) because i play peacefully.

factory
if(pq >= 9) factory
if(pq >= 10) factory
if(pq >= 11) starport
lab
lab
market
farm
entertainment
embassy
if(pq >= 12) fill the rest with labs

and I always use the best bonus tile available for a given improvement

Anything 10 or above gets a farm, a morale building, starport, 4-6 factories (8-10 if the planet is big or it is later in the game), and the rest filled in with economy buildings. Research is crammed on extra planets and a tech capitol. Small ones get wonders rush buyed on them, especially the morale ones because they are so cheap and the AI generally ignores them.

I tend to focus my planets. First I take a look at what the planet has and what I need. If it has farming +% tiles, I make it an influence/economy planet. Research +%? Research planet. And so on and so forth. I always first put down 4 factories, and then start on the other buildings. I never build starports on planets that I don't intend to use them on, and I normally end up with 3-4 high PQ construction planets with 250+ Military Production. My military never hurts for it, because I can churn out ships fast enough for my needs. I also always make a single-engine small fighter craft, and spread it across my planets to protect me from surprise attacks. Does anyone actually use tiny hulls?

I use my home planet as an industrial planet. I dont put any labs or influence items on it. Only things that have to do with industry and military. (and of course one farm and entertainment center just so i get some money). Then i colonize two more planets and one of them is my money maker having only farms, entertainment, and influence items. The other has labs and the like. Then I make a massive military force and destroy everything and use captured planets to make a variety of things.

I'm glad this thread got resurrected. Though there's variation here there is pretty much one common theme and that's starting with one or more factories sometimes bought sometimes not.

I think the size of galaxy and number of opponents makes a big difference in effective build strategies. If you're looking to at least keep parity with the AI's colonization at crippling and above, in a huge or gigantic galaxy, I find that buying or even building a factory first limits my colonization rush because I run out of money too quickly.

I'ved sucessfully used the following build sequence; adv market, farm, factory, factory, then variations based on the planets PQ. I also never buy the market or farm though I will often buy the factory once it starts to build on it's own. I skip the farm on anything less than PQ7, though I also usually avoid colonizing anything less than PQ7 until my economy is on a stronger footing.

The reason I use this sequence is that the adv market and farm have no support cost whereas the factory does. This sequence allows time for the pop to build up (increasing income) on the planet so by the time I add the factory the planet can pretty much support itself without being a drag on my economy. I find that this allows me to colonize more planets at a faster rate. There is some downside in that my production lags somewhat with respect to building a factory first.

I've found that when I've used a sequence starting with a factory what ends up happening is once I get the planet built up a bit I end up setting the focus on it to research anyway so why was I in such a rush to build a factory?

I prefer to specialise my planets, depending on the game parameters, and if I've just "acquired" alot of planets. There are 3 main area's I focus worlds on:-

Industry: Starports and lots of factories.
Research: Many research labs.
Credits: Lots of farms, entertainment and trade centres/banks/stock markets/etc. I prefer to call these Hive worlds were the population can be huge.

The hive world means I can concentrate my money improvements on a few worlds. The industry and research worlds don't benefit from them much as the populations are relatively small.

The advantage is high efficiency.

The key disadvantage of this is worlds can become critical to your empire, and, as they lack large populations, need heavy protection.

The thing I have found out that in 1.3 things have changed drastically. I can no longer on Challenging use my old strat of Special Planets. So now I might have to try a few of the ones in this thread. The thing with special planets is that you are so limited in game. (IE building ships, along with the tough economy now)

Played 2 games so far and by mid game I cannont keep up with AI military. And if I go to war its pretty much over for me. Guess now I will try to build Planets, with most of them having Starport.

Note this do not count special ressources. I usually try to get planets with same pop so it is easier to manage. I also build 1 or 2 supermanufacturing powers.

Usually:
Factory(Purshase)
Factory
Factory (if PQ >8)
Factory(If PQ > 10)
Factory (if PQ > 15)
Starport (If PQ > 9)
if i have extra pop available (ie i can move population from other colonies)
Marker
Farm
Market
Market

if it is a research planet
Research (if this is a research planet).
Research
Research
Farm

Specialization.
I only put research on planets which would have access to 3-4 economic starbases. Since this reasearch and production are 2 times cheaper i should get as much of it as i can.

Note i still play the easy crippling mode large map with 9 civs (ie easy). The strat may change if i move to bigger maps and on harder difficulty.