Where can I find a collection of density functional parameterizations? I want to implement a solution to the electronic Schroedinger equation using DFT. I know there are many, many functionals to choose from but don't know where to start. I'd like to start with a couple LDA and GGA functionals, is there a good place where I can look up some parameterization, or even the tabulated data itself to form my own parameterization?
Unless you are doing it just for fun and curiosity how the think works, you are better with some existing library. Most prominent is the libxc, offering the lowest level interface, i.e. given density (and possibly gradient) at series of points, it returns the energy. What is left for you is the construction of the grid and optimization of density, ie. you can go for the real Hohenberg-Kohn DFT, not just Kohn-Sham. For the usage examples (of the really nice and simple interface) see http://www.tddft.org/programs/octopus/wiki/index.php/Libxc:manual

And most importantly, you can find definitions of all the functionals in the list of implemented functionals