What is your favorite cloud app? I used to love iCloud on my iPhone but no iPhone no iCloud lol. Right now I'm trying to limit my use to just ONE. I currently use Dropbox and SkyDrive (from the internet browser since no app yet!). I know Google+ can upload your camera pics on the cloud but word on the streets is that Google is coming out with the GCloud but I kinda hate Google+ (Facebook is more than enough...)
DropBox for most files. Google Docs (future Google Drive) for office-like documents. Google+ (Picasa) with auto-upload works really well to upload photos into the cloud (and you can edit the photo into the cloud) Spotify for my music.
I like all these cloud services because they are accessible from all my devices (Windows, Mac, Linux, Android, iOS ...)