Shaner, N. C., Steinbach, P. A., and Tsien, R. Y.
A guide to choosing fluorescent proteins.  Nature Methods 2: 905-916 (2005).

The recent explosion in the diversity of available fluorescent proteins (FPs) promises a wide variety of new tools for biological imaging. With no unified standard for assessing these tools, however, a researcher is faced with difficult questions.  Which FPs are best for general use? Which are the brightest? What additional factors determine which are best for a given experiment? Although in many cases, a trial and error approach may still be necessary in determining the answers to these questions, a unified characterization of the best available FPs provides a useful guide in narrowing down the options.