My main computer is a MacBook Pro and I use Time Machine with an external USB disk drive. I use an externally connected USB drive instead. I recently got a 1TB drive for about $100 and have been using that after reformatting it with Disk Utility. Costco or other local stores sell the same kind of drives. I also have an older, smaller drive for an offsite backup that I keep in my work office. Whenever I change backup disks, I select the new disk in Time Machine Preferences.
For my iPhone, I keep my info in "the cloud" using google apps like: gmail for contacts and notes and google calendar. This allows me to make a change on my phone or any other computer and automatically see the change from other locations. Unfortunately, it's not totally straight forward to set up, though it's easily googled. The data that's left such as photos that haven't been uploaded to my flickr account, I sync regularly to my laptop at least once a week.
The ideal backup solution would be a fast and multiple site solution. You want multiple site, in case there is a fire for example. Computer backups are often large and thus a large bandwidth (quantity per unit time) helps make them fast. In particular, the initial backup may be large and will require a significant time to complete. Incremental backups after the initial one will be smaller because only differences will be saved. Hardwired connections like a USB drive are fastest, then Time Capsule which is over a local WiFi network, then the slowest would be over your home Internet connection. The basic tradeoff is that fast means an attached disk while a convenient solution to an offsite location is the slowest. I've heard of people using a convenient offsite solution such as Carbonite or other similar products. However, I haven't tried it since it costs money and I would suspect backing up my initial multi-GBs of data would take too long over my Internet connection.