in the "Phinx" version of PCLOS is only one theme available ("Phinx 2011"). Where can I download additional themes (I don't like the default theme very much)?
Try these two sites:http://xfce-look.org/http://gnome-look.org/
Any gtk2 theme or metacity should work for you. There are probably a lot of other sites, but you should be able to find a few things to brighten up your desktop at one or both of those sites.
Also, I don't have Phinx installed on any of my computers at the moment, but if you go to Synaptic and run a search for 'themes', you should find a few options already in the repositories...
I understand where you are coming from -- I am always looking for a fresh bit of 'eye candy for my desktop. I hope these suggestions help.