Exiv2

'organize' is a command-line tool that creates organized directories of photos and other media files. Photos can be easily organized by metadata into a directory structure of your choosing. It is built on Exiv2 and currently supports a fairly wide selection of exif, iptc, and file metadata (xmp could be added if there is demand).

I created this tool after looking around for an existing solution and finding no great options. My own personal photo library had become a jumble of 15,000+ files in a hodge-podge directory structure. With this new tool I ran the following:

organize /var/photos /var/photos2 @year-@month/@day

And a few minutes later had an organized library with photos and videos grouped first by year-month and then by day of the month (with duplicates filtered out). On windows it would be very similar:

organize c:\users\public\pictures c:\users\public\pictures2 @year-@month\@day

There are currently no prepackaged binaries, but I will try to get some uploaded soon. The tool is fairly easy to build on Windows and Unix like systems. It builds separately from the rest of Exiv2 because it has an extra dependency on the C++ boost library. To build the tool, first make sure you have boost installed, then build exiv2, and then build the organize tool. On Windows there is a project file in exiv2\msvc\organize, and for Unix systems there is a makefile in exiv2\contrib\organize (in both cases you may need to tweak the include and lib dirs to point to boost on your system).

Below is the tool's help output to give you a better idea of what is does. Let me know if you find is useful or have suggestions.

Usage: organize [options] source-dir dest-dir pattern

  Creates groups of files in new directories defined by a metadata 'pattern'.
  Files are copied, moved, or linked from 'source-dir' to 'dest-dir'.
  The destination directory should not be within the source directory.

Options:
  -m [ --move ]            move files rather than copy
  -s [ --symlink ]         symlink files rather than copy (posix only)
  -o [ --order ] arg       order and types of metadata to read
                           e=exif, i=iptc, f=file (default: eif)
  -u [ --unsorted ] arg    special directory to store unsorted files (default:
                           unsorted)
  -d [ --dups ] arg        special directory to store files with duplicate
                           names (default: duplicates)
  -f [ --force ]           overwrite duplicate files instead of using special
                           directory
  -r [ --rename ]          rename duplicate files instead of using special
                           directory
  -i [ --ignore ]          ignore both unsorted and duplicate files instead of
                           using special directories
  --ignore-unsorted        ignore unsorted files instead of using special
                           directory
  --ignore-dups            ignore duplicate files instead of using special
                           directory
  --verify                 verify copied or moved files and exit if incorrect
  -x [ --exclude ] arg     exclude directories and files that contain arg (case
                           sensitive on all platforms)
  -l [ --limit-depth ] arg limit recursion to specified depth (0 disables
                           recursion)
  -v [ --verbose ]         prints operations as they happen
  -n [ --dry-run ]         do not make actual changes (implies verbose)
  -h [ --help ]            show this help message then exit
  -V [ --version ]         show program version then exit

Pattern values:
  @date   date captured (2009-01-19)
  @year   year captured (2009)
  @month  month captured (01)
  @day    day captured (19)
  @time   time captured (14-35-27)
  @hour   hour captured (14)
  @min    minute captured (35)
  @sec    second captured (27)
  @dim    pixel dimension (2272-1704)
  @x      pixel width (2272)
  @y      pixel height (1704)
  @make   device make (Canon)
  @model  device model (Canon PowerShot S40)
  @speed  shutter speed (1-60)
  @aper   aperture (F3.2)
  @iso    iso speed (400)
  @focal  focal length (8.6 mm)
  @dist   subject distance (1.03 m)
  @meter  meter mode (multi-segment)
  @macro  macro mode (Off)
  @orient orientation (top_left)
  @lens   lens name (Tamron 90mm f-2.8)
  @key    first keyword (Family)

Examples:
  `organize -m mess clean @year-@month'
     Moves files from 'mess' into directories of 'clean' according to
     year-month the file was captured (clean/2006-11/...)

  `organize -o ie source find width-@x/height-@y'
     Copies files into directories according first to pixel width then pixel
     height. Check iptc then exif metadata (find/width-2272/height-1704/...)

  `organize -lf source find @aper/@hour'
     Force create symlinks in directories according first to aperture then
     hour captured (find/F3.2/15/...)

Edit: Updated to latest --help output