Ok, ok, this isn't REALLY a piece of photo gear, but has so many photography uses that I just couldn't help myself! You can also apply my comments to the iPhone for those of you that happen to have that little gem since the Touch is basically an iPhone without the phone (and camera).
So, what is the iPod touch? Well, first of all it is an MP3 player like most iPods - which I always regarded as over priced (even though I own shares of Apple!). But that is the least of what it is. It is also a fancy PDA (Personal Data Assistant) and has it's own operating system. So, it can run programs (and games for those who are so inclined). Some of those programs are quite useful - and very inexpensive - many are free!
How about a free flashlight? Ok - so who wants to spend a couple hundred bucks on a gadget that can act as a flashlight? Well, it can, but there are also a number of free alarm clocks for the Touch/iPhone. How about software that can tell you the tide - or show you when and where the moon/sun will rise/set? Check out Distant Suns for a terrific astronomy program. There is also a program that will currently allow Canon users to control their DSLR cameras by remote control. You can set ISO, focus, aperture, click the shutter and even see the results, as long as the camera is tethered to a network enabled laptop or desktop. Coming soon for Nikon users.
There are also programs to record trip details, check email on the go, and even a free pocket Kindle that will allow you to read eBooks while you are waiting for the perfect shot. The unit is really quite small and compact and will connect to WiFi hotspots to allow you Internet access.
I'm currently using mine to brush up on my Spanish with free lessons! There are a great number of free and paid podcasts for photography as well.