I have lots of color photos (RAW and JPEG), and want to see which ones would look good in grayscale, without having to explicitly convert all the photos.
Is there any software that provides this functionality? Having side-by-side comparison with color and B/W would also be nice, but it's most important that I can browse through photos in grayscale without explicitly converting and saving them.
EDIT: I am using OS X and Windows, software for either OS is fine.