I am particularly interested in Document Libraries, but in terms of general SharePoint lists, can anyone answer the following...?
The whitepaper I found most useful was linked from the resource posted by user mbowles above. The direct link is...
http://go.microsoft.com/fwlink/?LinkId=95450&clcid=0x409
In SharePoint v.2:
More info: http://technet.microsoft.com/en-us/library/cc287743.aspx
In SharePoint v.3:
More info: http://technet.microsoft.com/en-us/library/cc287790.aspx
The "2000 limit" expressed above doesn't hold.
Please take a look at this document for more exact answers to your questions.
I personally experimented what the document describes.