Every time I've played Civ 4 my first Settler starts on what looks like a pretty good square for a city, and I build it turn 1. Has anyone ever found it to be a worthwhile strategy to scout around a bit to see if there is a better location? If so how often is there one nearby?
So the map usually places you in a decent spot (ie. near good resources), but you can actually disable this option.
If you disable spawning near resources then the answer becomes very obvious. However, even in the case where you do spawn near good resources I always move my scout/warrior first to see if there are better resources I might want. I usually prefer growth based resources over military ones (ie horses) or commerce based ones.
In FFH2 (a mod for Civ4) you frequently start in "bad" locations, and I almost always move to a better location. Normally, I don't want my first city near Mana, as it doesn't help a ton to get up and running (when I have the option of other resources, obviously Mana is better than nothing), but I don't want someone else to steal it.
Another thing to consider is the size of your map. On smaller maps, moving your Settler is punished by running into other Civilizations. On larger maps, you usually have tons of room to look around and expand.
My take home might be: usually, just found your city where you start, but always make sure to move your Warrior/Scout first, just in case.
I have found moving to a square next to a river or coast to be massively useful, if my starting square is not. This lets you setup trade routes much earlier by researching the naval techs and connecting your cities by rivers/coast.
You can run trade off of rivers/coasts for a LONG time before you really need to connect your cities by road. Your workers can be off doing other things till then. This plan also has the nice side effect of making you want to settle along rivers, which boosts $$ income all by itself.
What do trade routes get you?
- More $$/Science
- Resource spreading, which gets you other effects depending on the resource...
- Ability to build units requiring resources immediately throughout your empire
- Faster wonders
- More happiness
- More health
Now... how many of those are worth more to you than a turn?* Get that important wonder you would have missed? Twice as many swordsman? Finish Alphabet first?
*Sometimes not even a turn. As @Kaestur Hakarl points out, settlers have two move points, so you can move and still settle if the move is onto a flat/open square.
Sometimes it is better to move your settler. Here are a few tips:
Move him to a hill for the best view of your surrounding land. To get an early start, look for a tile that has 2+ hammers. This is usually a hills/plains. When you plant your city on this tile, you get one extra hammer, meaning that you can create things faster. It does make a difference.
Look for a good food source. Every city needs a good food source to be strong. If you find a food source within the city radius of the tile that you want to plant your city, go ahead and do so. If there is an elephant next to your settler and food nearby, plant your city on the elephant. It will give you the extra hammer, plus save you a turn. The same goes with stone and marble nearby.
The best spot, however, is stone on hills/plains or marble on hills/plains because they give you 3 hammers in your city.