I recently got an iPad to ease my imminent travels, the (alleged) 10 hours of video and the ability to store a load of books will make the long plane journeys and layovers much more tolerable. The other big benefit is that when I get to where I am going I will be able to use it as a second monitor for my laptop.
Caius had previously suggested AirDisplay, an app that as it’s name suggests lets you use it as a wireless display for your computer (Mac and Windows) as long as they are both on the same wireless network. I bought it almost as soon as I got my iPad and tried it out in a coffee-shop. Throughout the day I used it for terminals and my Limechat IRC client and it worked well, staying connected almost continuously. The display updates fast enough for those simple uses, but stutters on web-page scrolling (though it’s still usable) and would be useless for video. Here’s a picture of it with a Textmate window dragged onto it:
AirDisplay is definitely worth a go if you travel with a laptop and like to have a second monitor. It seems to be a bit fussy with wireless networks though, I had no problems with a mifi wireless network and my 802.11n home network, but it wasn’t happy with my dad’s wireless network, it took ages to get it to connect and it got disconnected a fair few times. It also works on an iPhone if you’re really desperate: