When latitude and longitude are values filled out, it would be great to provide a link to GoogleMaps and GoogleEarth to go to the location where the photo is GeoCoded.
My preference would for the link to be available inside the IPTC info area (because that's usually where I'm usually asking the question -- where did I shoot this photo)? But it also probably makes sense as a right click option in the contact sheet.
The KML specification is pretty easy and hopefully wouldn't be too tough to implement inside PhotoMechanic.
Regards,
Greg