Just adding my $02 here,
I would use, NO, I do use, YYYYMMDD_JOBNAME_0001.ext given, that this way it will always be in chronological order. However, there are some issues with this and the above one, in that when you are making contact sheets or are sending things out for printing where they do numbering on the back of the print, they are usually limited by a set number of characters, in these cases, front numbering is a better option, but it makes it a lot harder to quickly find in a large collection IMHO
It will always be a compromise
Henrik
Agree w. Henrik. My goal is to always be able to find the originals, instantly. File length, as long as it remains 64 characters or less, is there to be used. Nevertheless, I front load the most important information. I rename all files on import.
yyyymmdd_JobName_####of####_Location_FileNameFromCamera.Ext.Date alone will get me close. JobName+#of# is very likely to be unique (with date it is unique). JobName+Location tells me (not the machine) what I need to know. FileNameFromCamera is unique (or nearly so), provides a good backup, and gives me a point from which I can extrapolate the other information if needed. The underscore characters provide a reliable way to parse the filename if needed.
The best discussion of file-naming (in this context) that I know if is in the Luminous Landscape Guide to DAM video tutorial with Seth Resnick.