In my years of maintaining the TikZ example gallery on TeXample.net, I also added plot examples. Those were mostly classic TikZ plots, not yet made with the pgfplots package. Since this package is extremely capable, I planned to place its examples on a dedicated page, to not mix it with pure TikZ examples. We already have about 350 TikZ examples there, so it may be good to not mix PGFplots into it, but have a dedicate site. Now it's here. Enjoy!
Did you produce nice plots yourself? Would you like to share it, here in the plot gallery? Then it would be great if you would send me an email to firstname.lastname@example.org.