I splurged recently and got an iPod touch; principally to show off my portfolio to whoever is polite enough to ask to see it. Seriously though, I think it's really a nifty idea to have one's portfolio in one's pocket. As we all know, the iPod touch is lightweight and lends itself superbly in terms of coolness and screen resolution to show off photographs in their best light.
Naturally, it has many other uses as well...and in the range of a Wi-Fi signal, I can also show off my portfolio and websites. I found I had to use the two-fingered scroll to do that...but the iPod touch is really worth it. It's really a 'portfolio-in-your-pocket', and is useful in many field situations for travel photographers.