Alamo: I beg to differ. One of my favorite tactics is to build my FP right next to my capital, then when I conquer a really nice chunk of land, fully developed by the previous owner, I use a GL to plunk my capital right in the middle of this new territory. This will give me two productive cores. The nearness to the capital will allow my new cities to build markets & libraries without having to deal with massive corruption, while my existing core will stay productive thanks to the FP. In the right conditions, I might move my capital 2 or 3 times in a game to develop new areas. It should be noted that once the capital leaves the second sight, corruption jumps, but once you've got you improvements (markets, banks, harbors, libraries & courts), you'll still be able to have happy citizens and be able to add (though more slowly) new improvements (universities & commercial docks, etc).
I should note that this tactic DOES NOT WORK in C3C.