Artifacts in Heroes III.

The power of dragons would be great if it only took up one slot... :) But as it is, I don't think it's very good...
I remember finding the "Helm of Heavenly Enlightenment" (or something like that) in a tomb during the first week. I was overjoyed... In my opinion, the most useful artifacts, without needing to be combined, are: the aforementioned helm, the Sword of Justice, and the Boots of Swiftness...