Does anyone know what font is currently being used by De Beers in the "a Diamond is Forever" ad campaign? I've looked through a few font books and can't seem to quite nail this font down. 

A Diamond is Forever looks something like Priori Sans small caps but the C and W don't match. Priori has the funky R.
The top one is Baker Signet.
It's funny you mention "diamond is forever" campaign. I've been on the hunt for the old "Diamond is forever" font for quite some time.
I think the bottom one is Documenta
Sans Small Caps
from the Dutch Type Library.
That face has the distinctive R.
http://www.dutchtypelibrary.nl/DocumentaSans.html
Captured from web.archive.org on 16 May 2005. view this capture