I usually go tall to start, and then see how crowded my neighborhood is. If I have room to grow and some prime city locations left, I will go for it and spread out quickly. I find that if I spread out too early, I end up with several under-producing cities that won't produce units fast enough when war eventually comes my way. However I typically fail to take advantage of national wonders because I am normally founding new cities once they start becoming an option.
on founding late cities:
I find it is totally worth it to found some late cities, especially for strategic resources, or a strategic location such as a naval base or beach head for an overseas assault. You can really get a city growing fast if you pile on the workers, buy aquaduct, granary, hospital, workshop, factory, etc. it is pricey, but if you have the cash, you need to spend it on something, I rarely buy units so I think buildings are a good investment. bribing CSs is a gamble unless going for a long term ally.