A good reminder to have offsite backups
If your everyday environment is VM's on the cloud then you don't need even that and you're good to go from any device instantly, but it's a bit too limiting for me - but keeping all data + portable executables with config on Dropbox is simple, and leaves actual backups only as emergency precaution for cases if the cloud services screw you somehow.
For personal data, Dropbox's versioning has been a lifesaver for me - if I have overwritten or changed something, I can get back also the previous versions; quite a few backup solutions don't keep the history. But for me the important data is various documents, so it's not that large - for example, I personally don't see the reason for making family videos, as even for our wedding video we just browsed through it once and haven't touched it in all the years afterwards, there's new stuff to do instead of watching old stuff.
I lost the last changes that weren't on the Subversion server (2005, remember). I resumed work the next day, from the slightly older/slower/noisier laptop the one in the backpack replaced.
The importance of off-site backups cannot be exaggerated.