If you are looking for a way to back up and synchronize your files across multiple devices (i.e. Mac, PC, Android, iPhone), check out Dropbox.com. You can save up to 2 GB of files free. You can also refer your friends and get extra storage added to your account.
Need more convincing? Check out this PC Magazine article that gives an in-depth review of the service and lays out the pricing options. Also if you are purchasing an HTC phone in the near future, Dropbox will be adding an extra 3 GB to the free plan for a total of 5 GB.
What other solutions do you have for backing up your files or accessing them everywhere? Share in the comments.