Ran into an error where when you browse a custom list for the first time after an iisreset the list would show an error message noting that it has been deleted such as The list or view of a list that is referenced here no longer exists.. If you simply refresh the page the list is there and usable until the worker process resets.
After some investigation, it all came back to the customized schema.xml file for the custom list. This is IMHO a perfect time to remind folks making custom lists that they really need to follow the schema.xml definition on http://msdn.microsoft.com/library/default.asp?url=/library/en-us/spptsdk/html/tscamlovSCHEMA_SV01084512.asp
The specific problem with the customized schema.xml in this case was that the toolbar element was not there at all.
In short, if you have problems like what I described--consider revisiting your schema.xml, make sure it includes what MSDN documents as required and reprovision your list object.
I will be making some additional blog entires at a later time dealing with site customization, best practices, attempt to make supportibility more clear, etc. This is a large topic for me--so I'll be posting information out a little at a time.