Adobe Bridge, with cs1 & 2 does a great job, if you have it.
If you don't, then the cheapest option I know is Acdsee, in any version, and the free older versions work fine, with the ghostscript plug-ins added (it'll ask you for them & they can be downloaded free, too), and it'll catalogue bitmap pictures happily, but it'll also catalogue & display eps files (not ai files though). The older versions can crash occasionally- that's life!
Extensis Portfolio I have not tried, but I've not heard a bad word about it!