Location:
I think it would be cool to see a person's GPS coordinates or Latitude/Longitude added. That way, if you're off in the woods or desert (or ocean) you can get back to that exact location (or plot it on a map) if you want.
Temperature:
Eh, just because, it'd be kind of cool to see the different effects the ambient temperature has on the CCD.
Distance to subject:
Is there some way to calculate the focus point the lens is using to arrive at a number for this? Of course infinity wouldn't work.
My Canon 28-105 lens includes the distance to subject... here's an example exif cut:
File: I40_0278-m1-640.jpg
File size: 148KB
Image Serial Number: 102-0278
Camera Model: Canon EOS 10D
Camera serial number: 1020300016
Firmware: Firmware Version 1.0.1
Date/Time: 2003:11:01 18:19:49
Shutter speed: 178 sec
Aperture: 22
Exposure mode: Manual
Flash: Off
Metering mode: Center-weighted average
Drive mode: Continuous: frame 1
ISO: 100
Lens: 28.0 to 105.0 mm
Focal length: 28.0mm
Subject distance: 655 m AF mode: One-shot AF
Image size: 505 x 640
Rotation: none
Image quality: Fine
White balance: Auto
Color space: sRGB
Saturation: Normal
Sharpness: Normal
Contrast: Normal
Tone: Normal
Custom Functions:
Default settings
My Challenge score so I can leave the reset stats buton alone durring the week also I can diside if it's worth the bandwith to upload and enter the pic in the first place