I either play the Americans or the Dutch. The Americans for the use of both the industrious and expansionist trait. Besides having the advantage of blanketing the map quickly with scouts, you do pick up a lot of early techs without real cost, and the settlers and the warriors you pick up are quite useful, as I go for monarchy quickly, and conscrip warriors make excellent, no cost garrisons. Once the map is explored, and the goody huts are gone, the trait is obviously much less useful, but then the industrious part kicks in for the Americans.
I use the Dutch because I like sea maps, and the combination of seafaring and agriculture is very useful. The extra food per city can be leveraged into extra shields pretty easy, and the seafaring gets me out and exploring fast. I have modded the curragh to carry one passenger, which makes it even more useful. After all, the curraghs used by the Picts and Celts in Ireland, Scotland, and Wales carried on a sizeable merchant trade long before the Romans arrived in Britain.