I'd like the ability to snap to an ArcGIS Server layer if its in my ArcMap session. Having the ArcGIS Server layer be vector would be fine. Not sure if this is available in 10.
Now that ArcGIS Server layers are becoming more prevalent as a way to share information between agencies, the need to use that data more like full blown layers (as opposed to little view-only items in ArcMap) is increasing. I'd much rather just snap to a read-only layer I’m referencing from another SDE, instead of copy it locally all the time, just to have the ability to snap to it.