Now I've had the Touch for two months. My observations:
It is a superb music player. Browsing through coverflow, or by looking at song titles is great. My one request would be a separate volume control.
Photos: My iPod Touch currently has about 2000 photos. The good news is that they look great. The bad news is that you must synch photos through iTunes. If you have big files, it may take a while. That's because the photos are cut down to size. What's stored on the Touch are not the original files. For Windows users, you put all sub-folders into a big folder and that's the one you synch.
As far as I have seen, the Touch does not have a disk mode, like some of the hard drive-based iPods. It will not function as a stand-alone backup device.
Videos look great. I've got all the DiveFilm episodes loaded.
Web surfing is surprisingly easy. The Safari browser is intuitive, but very limited. You cannot download any files from the web. The only thing that can be done by wifi is purchasing songs through iTunes. That works well, and when you synch the Touch, the songs are carried over onto the computer.
If I were looking for a data storage device, I would probably get an Archos 605, which has a bigger screen and a hard drive plus USB host. I don't know if it would let you view RAW files though. My travel computer is an old IBM X23, which is quite small and light. Between that and a portable hard drive I'm good.
I put a mini gallery up on my website:
http://www.pbase.com/krancer/ipod_touch