I voted yellow dot because it's/it'll be a good commerce or a decent GP city (2 rice, 2 dyes, 2 GL cottages [or two more farms with civil service], one GL-mine. Furthermore, coastal cities can help build boats. Although the yellow dot won't be a production powerhouse, every little bit helps. Our next city should be the production powerhouse.
In the dot-map thread, I think the red city is a trillion times better than green for a production city. It has two food and three plains-hills in addition to being a river-city (for health, more farms/workshops, and hopefully a levee later-on).
The green city in the dot thread is icky. In order to do anything it would have to take a rice away from the red city, thus lowering its (the red city's) production potential. Without that rice, it's a terrible city that could only work water tiles, one GL and one GLmine before shutting down. I don't think that the green city is worth it until much later in the game. Alternatively, when we do put it down, we could put The Statues there to rise it from horsehockey city to an ok city.
Lastly, having only three cities on our mainland for awhile will keep our score down and maintenence will be less of a problem. Probably most importantly, it will allow us to get that coveted neutral land quicker.