I was a very big fan of Keyword Editor. It has long since stopped being supported by the maker but it can still be downloaded at places like this
http://www.brothersoft.com/keywords-editor-83621.htmlAnyhow, it is a plug-in for photoshop that is very simple and effective. It spell checks, deleted duplicates, you can pick keywords from recent images, it kept the keywords in the order I put them. It simply worked very well.
Unfortunatly it doesn't seem to work in 64bit Photoshop - at least I can't get it to. Does anyone have a suggestion of something is just as good or has anyone gotten it to work with 64bit Photoshop?