Memory sticks are nice and all but to depend on it as your lone copy is taking far too much risk in my experience.
I've found that XP machines do have issues with the new larger sticks (the ones over 2GB) so you know when dealing with old gear to not count on your 8GB or larger stick to work.
And certainly no one would ever rely solely on a memory stick for the work.
Let me be more blunt and share my work flow. I edit my files and copy them to the stick. Then I may sync them to my DropBox. That way I have no less than 3 copies in case of any issue.
Basically I bought a memory stick from Kingston because I work from home as a tutor and I wanted somewhere to save my work. When I put the memory stick in the laptop and turned it on it said unable to read disk on a black background with white text. I took the memory stick out and then it booted up ok. I did some work on a word document and saved it, when I closed and tried to open it I got all the pages loaded with the word count but they were all blank. I found a fix where u delete somethin in the regedit (http://www.msofficeforums.com/word/8181-all-my-word-documents-opening-blank.html) I did all these fixes from this site. I then tried opening it a few more times and I got an error i think something mse46 and something to do with converting, after clicking the X the document opened but with all squares on it (I cant remember if I got the error before or after the fixes) I thought it was a problem with the memory stick so I went on the PC and found one of the first saved versions (before I moved it to the laptop and worked some more on it), this opened fine so I put it on the new memory stick and one of my old ones. On the new memory stick I got the same issue but on the old one I didnt. Today I turned my PC on and it took forever to load. I tried to upload work for a student and when I clicked browse to add a file it didnt do anything. I opened some word documents from the PC fine and when I went to save it worked ok. When I clicked save as it opened but wouldnt let me change the folder it just gave me the message 'initialising the root folders to display' I tried to click close and nothing happened, ctrl alt del didnt do anything, shut down didnt do anything I ended up turning it off at the plug. I have a 6yr old PC on XP and my laptop that I mentioned runs on Vista I dont know more about operating systems to give any more information and I was using MS Office (word) 2007. I have Microsoft Security Essentials and run Malwarebytes, Adaware and disk defrag pretty frequently and I run scans from MSE probably once a week. As you can appreciate working from home I really need my computer, I have the work on a memory stick but as the laptop is working OK I don't want to put anything in it that might corrupt it too until I know what I'm dealing with. It seems all the problems I had were since I got this memory stick I had no issues prior to it.