Best way to classify photo collection?

[andrea.ippo]

Hi everybody,
I have some thousand photos to classify, and actually I'm doing this by creating folders and giving to the files meaningful names.
However this takes a lot of time, and it would be much more effective if I could use the tagging mechanism instead.
So I come to my question:
what solution do you use to tag your photos?
Can I safely use the XMP format? (is it largely supported?)
Or do you suggest something else?

Thank you

[marsh]

Can I safely use the XMP format? (is it largely supported?)

It is generally available on all OS. And XnViewMP's support is mentioned on IPTC's Web - Software list.