I have heard the old advice for Windows NT 4 which, if memory serves, was a rule of thumb "memory size plus 12 MB" (so that a complete dump could be written to disk).
Does anybody have any recommendations for Windows Server 2003 and 2008?
(Also, while we are at it, what is a good swap file setting for a VM? Like physical machine or should I give more memory to the VM and let the host do the swapping?)