Everybody's easing into cloud storage, whether they know it or not. Remember when most webmail mailbox sizes were a measly 1-2MB in the 90s? Now, you get 10GB, easy.
Specific to cloud storage, I use DropBox (5.8GB), iCloud (5GB), Google Drive (5GB), and SkyDrive (25GB). All free.
That said, I also have my 10TB (5x 2TB) Homeserver to fulfill my family's PC backup and media storage needs.
Portable documents, I keep in my 32GB USB thumbdrive... which is synced to my notebook's Briefcase and backed up to my homeserver.