One or two turns missed in the very first stages only really delays your first unit/building by about two turns, and puts you two turns behind in research and culture. If you can move to a position that doubles your capacity for producing shields, beakers or culture beyond the starting values, it's definitely worth it.
For instance, Japan in the latest expansion produces +2 culture from atolls. Say you begin with an atoll slightly out of range: moving means you lose a turn of culture production (1) but every turn thereafter will give you 3 culture if the atoll is worked. Six turns in and you can hit your first policy, which snowballs from there.
There are tons of other reasons. If you start on a hill, you'll never be able to build a windmill in the late game, which has to be balanced against the extra +1 production in the city square from a hill (+1 production across the whole game versus being able later acquire +2 production, +10% when building and one engineer slot). If there's a river in sight you may want to move there so you can take advantage of the river specific buildings like waterworks or hydro plant.
They've made moving less and less of an issue with progressive games. It may have been suicidal in Civ 2 when you only had your settler, but now they give you a starting unit to help scout, and you can move the settler and still found the city if you don't burn all your movement points at once.
My rule is always to move the warrior to a tile that reveals as much terrain as possible before I touch the settler, so that I can suss out whether a move is worth considering.
Kuredan said:
I also have a compulsive habit of, when playing as Egypt, putting all my wonders in a single ubercity that is by the coast and one hex away from a mountain. Who doesn't doesn't want to visit the Colossus Stonehenge Library Lighthouse of Chichen Itza located in beautiful Thebes? Moar Wunderz!!
Ah, the Egypt theme park strategy. So dear to my heart. That was how I won my first one city challenge, even before Venice and the new culture rules made it terribly easy.