I've seen a lot of threads with people wanting tons of things for the new iPod. Although it is all speculation, and your guess is as good as mine, I'm trying to be realistic as to what the new Touch will have, based on Apple's history.
Plastic Backing: No
We all hate the metal backing of the iPod, but I don't expect that to change. It has been the backing of all of Apple's highest end iPods, and there seems to be no reason to change it. I think Apple likes the fact that it scratches so easily, it makes people want to buy new ones every year. Although there's no doubt a plastic backing would be welcome by many, I don't think it will happen.
64 GB: Yes
Seems logical. I don't think that Apple likes having the same maximum capacity on both the iPhone and the iPod Touch. The iPod is meant to be a media device more so than the iPhone, so it's only logical that the highest end model have more capacity. I would expect 16, 32, and 64 gig models replacing the current lineup and the same price points.
Fingerprint-resistant oleophobic coating: Yes
Apple quietly put this on the iPhone 3GS, meaning it's not a huge deal. Apple usually likes to play up even minor additions (i.e. MMS and Video Recording). So the fact they didn't play this up tells me its rather simple and I expect it to reach the iPod, also quietly.
Camera: Yes
Call me crazy, but I think this is going to happen. One reason was an Apple job listing looking for people to work on cameras for the iPod. The second reason is logical. Apple's 2G Touch was a very incremental update. It changed its appearance slightly, added a volume rocker, a speaker, and several other small changes. This was a very small upgrade, and Apple is not usually known to do 2 minor upgrades on iPods back-to-back. I think many people resisted the temptation to upgrade from 1G to 2G, and Apple needs to do something big to the iPod to get people to upgrade. So even though it's a toss up, I'm predicting it will have the same camera as the iPhone with video recording. It's the slam dunk new feature that Apple could use to drive sales of the device.
GPS: No
Would love to have it, but I just have a gut feeling you won't see it on this iPod. Can't explain it, just don't think it will happen.
Microphone: Yes
The inclusion of the Voice Memos application on the iPod Touch 3.0 software sealed the deal on this for me. It makes no sense to have a non removable app like that on the Touch if very few of its owners can use it. Out of the box, every iPod user should be able to use every Apple application, including Voice Memos. Although, I'm not necessarily saying the microphone will be on the device. In fact I think it's more likely the microphone will be on the headphones, similar to the iPhone's headphones. Just expect there to be a microphone somewhere inside the Touch's packaging.
3G: No
I don't know why anyone thinks this is possible. The iPod is not a cell phone.
Thinner: Yes
But only slightly. Ever so slightly. Likely unnoticeable.
Better battery life, faster performance: Yes
This is a given, every Apple product is always more battery efficient and faster than the previous model. It will be interesting though to see just how much better they get. The battery will likely only get incrementally better, but the faster performance is a tough one. It will definitely be faster, but whether it is incremental like the 2G Touch, or considerably faster like the iPhone 3GS, remains to be seen. I'm leaning more towards 3GS.
Compass: No
I think the average person is only going to use the compass on the 3GS to aid in using the GPS. Since the iPod won't have GPS (in my opinion), the compass is almost useless.
Voice Control: Yes
This makes sense. Since I believe a microphone will be included with every device, it's logical to include this feature.
Front-facing camera: No
This will never happen on any iPod. Apple is all about clean design. Nothing looks worse than a camera protruding out on the front of the device. It's ugly and I don't think Apple believes enough people would use the feature to warrant its inclusion.
Better speaker: Yes
The speaker on the 2G Touch is lackluster. Better speakers exist for the iPhone. Expect an upgrade, even though it likely won't be heavily advertised.
AM/FM Tuner: No
People have wanted this forever, and it will never happen. Never has, never will. Even more so now that there are apps that let you listen to radio over the internet.
Aluminum unibody design: No
While I could potentially see this in the future, you won't see it on the 3G Touch. I expect the Touch's physical design to remain very similar to the 2G model. In fact it wouldn't surprise me if it's identical (aside from the camera on the back).
So that's all I could think of, if I come up with more I'll update the thread. I think that the biggest new feature of the device will be a camera, and that will be Apple's biggest selling point. They can not do another incremental update to this device, and the only plausible huge feature they can add is a camera, so I think they're going to do it. A lot of people don't think they will, but two years ago we didn't think an iPod would ever have internet and look at the device now. We can't imagine it without it. So in my opinion, look for the new iPod Touch this September to include a camera, as well as the other features I described above.
