I love my iPod Touch. I don't want an iPhone because I can't afford the monthly data plans. Also, I can use my iPod Touch all day without worrying about using the phone battery. I use the apps on my iPod Touch daily. I have an armband and play music and use the Nike+GPS to track my exercise. I couldn't do that with an iPad Mini. I connect my iPod to my car radio and bring my tunes everywhere. I suppose I could do that with an iPad Mini, but it would not fit in the console and would get in the way. I couldn't fit an iPad Mini in my pocket, and I would have to have a large purse to carry it. I'd love to have an iPad, and maybe I would like an iPad Mini, but I don't see anything really replacing my iPod Touch. I hope it stays around for a long time.
If you are looking to upgrade your iPod Touch, I highly recommend buying an iPhone 4. (please keep reading!
) An iPhone 4 without cell service is basically an "iPod Touch Pro". It can do everything an iPod Touch does, but only better.
There are MANY iPhone 4 devices for sale on places like eBay that are mint/new that won't require a cell service. A CDMA-based iPhone 4 with a bad ESN can (virtually) never be used as a phone, but makes a great iPod Touch. And because they can't be used as a phone, the prices of them are suppressed in comparison to functional iPhones.
There are a few reasons why a phone ends up with a bad ESN. 1) it was reported stolen, 2) it was reported lost (and subsequently found), 3) the owner failed to continue to pay on the contract. Obviously you wouldn't want to encourage theft, but options 2 and 3 are morally acceptable and something to consider.
I own an iPod Touch 4G 64GB. I absolutely love it. I also bought a 3 month old Verizon 32GB iPhone 4 w/bad ESN (non-payment of contract) on eBay from a reputable seller for $240. It makes a terrific iPod... and because the cell radio and GPS are turned off, battery life is insane.
I have previously posted a set of common sense guidelines for buying an iPhone on eBay that will virtually eliminate the possibility of getting ripped off.
I hope that Apple upgrades the iPod Touch this generation, but if they don't and they put it in "steady state", getting an off-contract iPhone 4 makes a pretty nifty upgrade.