Depending upon your storage needs, desired backup capacity, desired speed, and budget, another option is Network Area Storage (NAS), a dedicated server attached via an Ethernet cable directly to your wireless network router.
I recently purchased an iomega/Lenovo 2TB unit to back up a MacBook with 500GB, a MacBook Pro with 500GB, and a 64GB iPad2: http://go.iomega.com/en-us/products/network-storage-desktop/ez-media/?partner=47 60
The server allows the use of Time Machine for the MacBooks, and has an iOS app for iPads and iPhones. While 'cloud access' to my backup files is one of the available configurations, I have not implemented it.
Initial Time Machine full-backup time was going to be somewhat long (over 24 hours) for my MacBook using my wireless setup, so I connected my MacBook directly with an Ethernet cable, and cut the required time down to under 8 hours. (The other two devices aren't nearly as full.)
I've had it installed just about 30 days, so I can't comment on long-term ownership, but it is working well for my modest backup needs.