I’ve been using Pandoc for generating most of my documents for some time now, even going so far as to write a small tool to add additional support specific to my needs. I mostly generate PDF documents, and I found it quite annoying to have to close the PDF viewer (I was using Acrobat) to allow Pandoc to make a new PDF.
I have since discovered that the Sumatra PDF reader will allow PDF’s it has open to be written to – I’ve been using it for a few days and it seems a nice solution to this little problem.