I never rely on my host for back-ups. The small amount of time to back-up can save you hundreds of hours should something happen.
I will backup as well :P to backup I download all my files via ftp, how do you back up?
Backup is very important,you should always backup everything from your blog->site->desktop->backup disk->NAS
I tend not to trust online backups - I don't feel safe with my data in someone else's hands.