It is always good to keep up on Windows Updates but this one is particularly interesting because it is a public release of the newer NT kernel builds. A lot of people won't care about that aspect, but if you have been wanting the BDD XP kernel fix for the NTFS alignment issue, or needing the multi-core XP kernel update, this is your one stop shop for those updates now.
Read about MS07-022
here.
For those tracking the XP SP2 kernel build revisions, it seems to be up to 3093.
Update: I might be wrong on the BDD fix - see below from a comment left from Arian:
This update contains QFE and GDR fixes.
I think a user who has never installed a hotfix he would get the GDR fix which does not contain the hotfix 'branch' as a QFE update does.
So to my knowledge a GDR fix could probably not contain the BDD kernel fix.
So I think it does matter what update a person would get from this public released update.