Just got this via email. Click to go the site: http://resources.arcgis.com/content/patches-and-service-packs?fa=viewPatch&PID=160&MetaID=1840
There is a massive list of fixes here: http://gisupdates.esri.com/10sp4/ArcGIS/ArcGIS10sp4-issues.htm#desktop-sp4
I wish it was organized a little better – considering there must be a few hundred enhancement it’s hard to look for specific things that I want to check.

