Computer File Archives

Fast-forward 10 or 20 years.  Your life is on your computer: recordings, pictures of your family, stories you've written, journal entries, address book, etc.  Can you open them?  Some formats are universal or at least open and transparent.  Others are proprietary (m4a) or obfuscated (.doc).  People are already discovering that their MS word files from the 90's won't open any more.  

Also: filenames are forever.  Directories (folders) are pretty reliable.  Any other metadata will probably get lost.  Give your files descriptive filenames and place them in sensible folders.

Protect your archives!

My suggestions:

Text: .txt (ascii), .html; .rtf ok.  If you can't read it in emacs you're in trouble. 
.pdf only as neccesary.  
CRITICAL: If you use .doc, export an archived version to something plaintext!

Audio: .wav, .aiff, .mp3. 
Use the iTunes preference "Keep Media folder organized". 
mp3's keep metadata in the file, so fill out the info; it'll survive.

Images: .jpg, .tiff ok. 
Archive photoshop format to something else. 
Prefer .png to .gif. 
Watch out for iPhoto because it obfuscates the directory structure.  When I dump my camera I run a program (http://ned.resnikoff.com/software/pixdate/index.html) to give each photo a date-based name (eg 100331_01.jpg) for archiving.