When using AUCTeX with pdflatex, one can run
C-c C-c (
C-c C-v (
TeX-view) to spawn a PDF viewer.
I use Evince on Debian Wheezy, in case it's relevant.
This might sound a little absurd, but I find it easy to lose track of where the Evince viewer attached to that particular buffer is. Sometimes it can be buried under other windows or mostly off the screen. I run other instances of Evince too. If it makes any difference, I've got Synctex at least partly working.
So, is there some way of telling emacs/AUCTeX to "find" my Evince viewer, or failing that, is there some convenient way to tell emacs/AUCTeX to kill the viewer and start a new one?