This is a great idea for notebook owners who are often copying data to and from their lappy using the typical USB connection. A.C. Ryan have developed the "eSATA ExpressCard34 2-port", which as the name implies adds an eSATA port to your notebook via an ExpressCard slot. The device is also available in a PCMCIA format for older notebooks as well.
In case you didn't know, eSATA is significantly faster for external data transfer compared to USB2.0. So if it's large amounts of data you shift from time to time, this could be a great investment for you.
For more details check out the product page on AC Ryan's website.
Ran out of space on your notebook harddisk? Why settle for slow USB speed. In these days of gigamania, watching and waiting for that file to stroll across USB must simply be not acceptable. Move into the gigabit data generation and eSATA your notebook now.
With the ExpressCard34 format, you'd be able to use this in all ExpressCard slots - irregardless whether your notebook has a 34 or a 54 format slot - it works in both!
Also available in PCMCIA format mainly used in notebooks before 2007.