eswphoto is a slideshow viewer, designed for digital photography enthusiasts. Features include: intuitive control (no distracting GUI), zoom and pan feature, full screen, fast, EXIF tag display, high quality scaling, lossless image rotation.
It currently runs on Windows only, but it is written in Python and shouldn't take much work to get running on other operating systems. I haven't had a chance to try it on any unix-type OS'es yet.
To get started: download, install, read the readme. right-click on a folder containing photos, click 'send-to', then click eswphoto. Press F1 to see what keys do what.