Google Drive. My to-do list is on Workflowy. My music is on Rhapsody (except for the stuff that isn't). My photos are on iCloud, and I'm planning to double up on Dropbox. A couple years ago, my work computer crashed and I just grabbed a random laptop and barely skipped a beat.
The cloud is idiot-proof, which is great for me since I'm an idiot. Now I can drop my phone in the toilet without incident! No more forgetting to email documents to myself, or losing flash drives. I still prefer Powerpoint to Google Presentation, but if I forget to close the file at home, it's not updated at school. But Google Drive saves with every keystroke. That's exactly the kind of idiot-proofing I need.
Plus, it's called The Cloud. I love clouds!