I got an early birthday present of a netbook just before our last cruise and took it along. We never used the internet connection on the ship, but used it on shore. Most ports have either a wifi hotspot or a place where it is very cheap to sign on and it is faster than the ship's internet. We used skype to talk to people back home a couple of times, but mostly just a quick e-mail update.
The netbook is small and light to carry so it was no problem to take it with us. Otherwise, we wouldn't bother.