The first module of the ISS was launched in 1998. 13 years and somewhere between $35 billion and $100 billion later, the final assembly of the ISS was officially completed today with the installation of a laser-equipped extension boom for the station's robot arm.
Just because the official construction phase is over doesn't mean that the ISS isn't going to expand further. The Russians are still planning to add another science module in 2012 called Nauka which will likely be the last major component to the station, although there's still the potential for other people to add even more modules, like Bigelow and their inflatable habitats.
They also might stick some extra toys on the outside of the ISS at some point; that VASIMIR thruster is rumored to be putting on an appearance to help the ISS hold its altitude, for example. And honestly, now that we've spent so much effort on building the thing, we really should cram as much science and technology in there as we can, don't you think?
So now that the ISS is more or less completely finished, you can enjoy the gallery below while thinking about how awesome our species is to have actually followed through on this permanent international outpost in space.