First off,
the WPS Gallery @ Rockbox serves this exact purpose. I'll assume we're gonna have this thread here too for those who don't frequent rockbox.org too much, but it would be nice to post your WPSs there as well as here.
I decided to work on a theme a while ago, with the advent of images implemented into the WPS. However, in the end I decided to go for simplicity, and I'm very happy with the result, so much so that I've been using it since. I used the Snap font (which seems popular), but it should work adequately with any font of the same size.
Code:
%?ia<%ia|%d2>
%s%?it<%it|%fn>
%?id<%id|%d1>
%pc/%pt
%pb
%pp of %pe %?pn<(%pn)|>
_____________________________
%pr until:
%?Ia<%Ia|%D2>
%s%?It<%It|%Fn>
%?Id<%Id|%D1>