ESRI have released the first service pack for ArcGIS 10. The list of fixes is enormous and having encountered several of the bugs so I would highly recommend you perform the update. The ArcGIS Desktop 10 service pack is 361mb in size so make sure you have a decent internet connection.The download page is here. When I tried it I was getting a download speed of less than 1mb/ sec so if you administer for multiple users it may be worth uploading the file to your own server. It is reasonably straightforward to install. Simply double click your downloaded file and follow the steps. Don’t believe the estimated time remaining as it said 2 minutes for me throughout the installation that took approximately 5. If you rely on a license server you may need to re-approve the external connections required and then re-open ArcGIS Desktop for it to work.