Couple programs I like...
Paint.NET, Irfanview and The Gimp.  You can now get Gimp to work in one
main window instead of 3 now, look for Gimpshop.
However I do not know if these work with 64bit.
Have you also looked at the photo editing within Vista?  Not sure what
level of photo editing you want, but Windows Photo Gallery will do basic
functions like adjusting colour, exposure and red eye removal.