I totally agree with your statements about the advantages and disadvantages of cloud computing. I love that I dont have to find my little USB drive all the time or worry about updating files - which drive/computer has the most up to date version of a document? Drop box and google docs have got around all of that. Magically I can also see both on my Ipod if I want ( dont have an iPad yet!).
I also do back up to a portable big drive - well notebook sized - in case. I don't trust any technology completely for reasons of experience. I agree it can also be scary when a particularly successful cloud app gets bought and then either disappears or changes to something I don't like. I was very nervous about what I was going to do with all my delicious bookmarks when things changed there but it worked out fine.
I dont always have reliable access to the internet and unfortunately this is most often a problem at work. Travelling can also be difficult but that is where my portable drive comes into its own and dropbox updates everything once I have Wifi again.
Having a lot of web-based information is useful for someone who moves around on teaching contracts and enables me to keep my blogs and bookmarks and documents handy without worrying about an employer thinking they might 'own' any of this. On the other hand they usually still have access to my shared information when I move on which fits nicely into my own preference for open access.
Keeping an e-portfolio (currently in development) on the cloud is also useful for all of the reasons given here as well as providing potential access to any searches from future employers.
Being able to move easily from computer to computer - 1 in the office, several in classrooms and 3 at home - all with different OS- and sharing files is so much easier with cloud computing. I am yet to convert my colleagues but we will get there
