iPod vs iPhone
There's nothing you can loose with the hacks and it's really simple.
The touch becomes almost a PDA when you hack it. And you get a glimpse at the future whene the SDK will be available and 3rd party apps will start to pop up.
I had the chance to play with the iPhone in the store before the iPod touch was announced, and knew such a device was in my future. I'm tied to another contract, though, so I watched the unlocking unfold. This process, I knew, was not for me. So I rejoiced when the iPod touch was introduced and described as the iPhone without the Phone.
I rationalized the lack of Mail, Weather, Notes and editable calendar as saying I could do these things through other sources. And for the first week, I believed it. I loved the iPod functions of my touch but felt... I don't know, like it was only living up to half or even a quarter of its potential.
So I did it. I jailbroke it. Now it's truly an iPhone without the Phone (or camera, but hey.) It's so useful... it's a toy and a tool. It's my first real mobile device (had a basic cell phone but nothing more) and even after two weeks I don't know what took me so long to get one.
Truly, knowing what I know now, if the iPod wasn't hackable, I'm not sure I'd buy one for myself. Not that it's a lackluster, horrible device without the added apps... but it's so much more with them.
I will watch with interest how the SDK changes things, but for now, jailbreaking is where it's at. Do it. And if you don't think it's worthwhile, restore it.
Nothing ventured, nothing gained.