One of my favorite sites is the Berks County Association for Graveyard Preservation on Facebook http://www.facebook.com/media/albums/?id=150047911461 -
Here you can dig through their albums and find headstone pictures; note - as they are doing cemetery restoration and preservation, they are not creating individual memorials on FindAGrave.com
i just found out some information by using iowa gravestone photo project for a great grandfather and grandmother in clinton iowa.
Hunting Kiwis has headstone / cemetery info for rural Canterbury in New Zealand.
Is this the sort of site you're looking for?
How about billiongraves.com
FYI, www.findagrave.com now appears in Family Tree Maker/Ancestry.com as a 'shaking leaf' hint. That said, not all the memorials are fully correct, but then the same applies to many other sources (e.g., census and other docs if not transcribed properly, millenium files, directories ... and the list is endless). As good researchers - we follow the leads but need to validate sources and add appropriate comments for others who may view our research.