I just saw a thread about Kodak DCR files. These are the file types most people think will become obsolete soonest.
At work, I have about 15,000 DCR files in my archive that I will be converting to DNG. I have DCR and CRW files and I want them all in the same format. I have 150,000 CRW files that I am going to convert to DNG.
I also just deleted 45,973 TIFF files from my server. It was a scary moment but I feel better about it now - http://digitalphotorepro.blogspot.com/2011/06/archive-deleted.html