Here what you can do with the data cable:

Charge the battery – It’s nice upgrade from the E71, the data cable also charges the battery.

Once the cable connected following option menu appears:

PC Suite – When selecting this option from the phone menu, you can use the new OVI software to backup the phone contacts, SMS, pictures, install new maps and application. if you didn’t install the application you can download it from here. Although bluetooth supported as well, physical cable always works better. Additionally most if not all firmware updates supported only when connecting using a cable.

Media Transfer – When selecting this option you can use the windows media player to sync pictures, music and videos. I tried it but didn’t like it.

Picture Transfer - When selecting this option you will be able to transfer pictures from the E72 like it was a camera. you an use your favorite picture mangment software, picasa for instance to import the pictures.

Media Storage- forgot your USB stick? no worries select this option and the E72 will act as a disk on key.

Connect PC to the Web – If you have 3G data plane you can use this option to connect you laptop or PC to the internet. you will need the “Nokia PC Internet Access” to use it. But no worries if the software is not installed on the laptop/PC you can install it when connecting the cable for the first time.

The default behavior can be changed to suite your needs, go to Menu-> Ctrl. Panel-> Settings-> Connectivity-> USB. USB mode –  Default behavior when connecting the cable. Ask on connection – if changed to NO the option menu will not appear when connecting the cable.

It’s a small cable with many options, why not to carry it in your case?