ESRI just announced that is is releasing 10.1 – there look to be a lot of enhancements. For the full list of changes, here is the 169 page document: Whats new in ArcGIS 10.1 (.pdf file)
Here are some that I find interesting on the server side (I’ve extracted the text from the document).
Connect to ArcGIS Server with a ‘Publisher’ role
In previous releases of ArcGIS Server, you had to connect to the server as an administrator in order to create or update services. In 10.1 you can now assign users the publisher role. This way you can allow users to publish, stop, and start services without giving them access to advanced administrative tasks such as adding machines to a site.
New logging framework and user experience in Manager
At ArcGIS 10.1 for Server, logs are distributed among all GIS server machines participating in your site. It’s recommended that you view and query the 10.1 logs using ArcGIS Server Manager or the ArcGIS Server Administrator Directory, rather than attempting to sort out the logs on your own.
Map services allow clients to change layer appearance and behavior dynamically
Clients of ArcGIS for Server, such as the ArcGIS web APIs, can change layer appearance and behavior in a map service dynamically. Behaviors such as which layers will appear in a map, layer symbology, layer order and position, and labeling can be achieved on the server through the use of dynamic layers. In this way, dynamic layers can increase the amount of interaction that users are able to have with your maps.
Batch geocoding using REST
In addition to finding single addresses and performing reverse geocoding, you can now do batch geocoding using REST.
You can get detailed status reports on your cache as it builds
For any cached map, you can now request a report showing level-by-level statistics of cache completion status. You can also view the status of each caching job you’ve submitted.