I found an all in one document viewer called "STDU Viewer" the web site is posted below:
http://www.stdutility.com/stduviewer.html
I have tried it out on my desktop and it works for TXT, TIFF, PDF and DjVu. It will even open the pdf's that SumatraPDF has problems with.
So I was wondering if it would be possible to make this application portable it would cut down on the amount of document viewer apps. swaving space for everyone.