For backups I've been using Amazon storage and Azure. Both work about the same. If you do go with Azure, I strongly recommend getting a copy of Cerebrata's file management software. It'll make your life a lot easier.
Red Gate Backup automates the copy of the files after you finish your backup. We'll manage the storage for you too. It's currently residing in Amazon.
"The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood"
- Theodore Roosevelt
Author of:
SQL Server Execution Plans
SQL Server Query Performance Tuning