NEX File Folders on SD Card.. By Day???

I suggest to add your photos in the following order:

\2012\March_01 _02 etc....
\2012\April
\2012\May

This way you will be able to track all your images by date.

I also assign a folder for each camera I use:

Nikon D700\2011\Jan\.....etc
Fuji X100\2012\Feb\03... etc

So I can keep track of all the different files shot with different cameras.

Hope this is useful to you.