If you are running Windows, I would just use the default Image Viewer, coupled with Thumbnail View on the folder containing the images. It works.
EDIT: Well, at least Thumbnail View works in XP, I was just quickly looking and couldn't find a way to set it in Vista. Does anyone else know how?
There are others...
ACDSee: which I was a big fan of in version 4, but has now IMHO become bloated and unwieldy. Too much packed in. Costs money.
http://www.faststone.org/FSViewerDetail.htm: like ACDSee, but a little lighter. Especially in the wallet! Freeware.