As an owner of the iPod Touch 2nd Generation and iPhone 3G, I'm really not impressed with the new iPod Touch 8GB 3rd Generation that was released. It's simply the updated version of the second generation model. It has the same exact look as the second generation Touch pretty much as how the iPhone 3GS looks almost exact to the 3G.
After using it for a few hours as of writing this review, I really didn't know any difference compared to using the second generation iPod Touch. Performance is mostly the same and all the features as well so there's really not too much to write about. I was really anticipating it to have a lot more since I heard rumors it would have a camera but apparently it doesn't. Overall it's not a bad device anyhow since I didn't have to pay anything for it after getting it for free from Amazon through an online survey site. I'm just going to probably sell it soon. If interested, check out the place I got it from.
In short, if you are considering getting an iPod Touch 3rd Generation for the first time, it's worth doing so since it's such a great and useful device to have. However, if you plan on upgrading from the second generation to the new 8GB version, it's really not worth it at all.
So if you want an 8GB iPod Touch 3rd Generation, you should buy the second generation if you can find it at a cheaper price rather than getting the 3rd since there's no difference really. If you have any questions regarding my review, feel free to leave a comment!