I will try to use popular file formats when possible. Here's a list of extensions you might find here:

PDF for Acrobat reader
WAV for Windows' sound files
DOC for MS Word 6.0 for MS Windows 3.1 document
PLT for HPGL or HPGL/2 plot (see HPVIEW.ZIP in utilities to view)
DXF for Drawing Exchange Format graphics file
GIF for Graphics Image bit map
TXT for Standard ASCII text file
ASM for Standard ASCII file (assembly code listing source file)
AVI's are movies and JPG are picture files

If your browser does not support these formats, plug-ins are available on the net that will allow viewing or listening to the files