Let's go back a bit in the Mac mini history. A rumor indicates that the Mac mini was developed following a request from some shareholders for a true entry-level desktop computer, while Apple had no real plan for such hardware.
Of course, we do not know if it is true or not, but the past Mac mini history and the lack of interest from Cupertino to upgrade it regularly, tends to confirm such hypothesis. Even recently, instead of upgrading its CPU/GPU/HD or other features, Apple decided to simply cut the price.
Of course, one can see such a move as a sign for a product to be soon declared "End-of-Life", not only to be upgraded but to be entirely dropped as a hardware model.
This is particularly true with the recent announcement of Intel's ATOM CPU. Of course Apple knows about such CPU way before Intel even started talking about during the last IDF. The ATOM CPU is targeting entry level computer as well as mobile computing/internet handheld. For sure it is not as powerful as the Core 2 Duo, even the ULV models, but it cost much, much less, and would make it possible to develop desktop computer for 200 to 300 USD. In such conditions, the interest of the Mac mini will be reduced, as it will remain more expensive while not being loaded with all features required to be consider as a mid-range desktop model.
In addition, Apple is more looking into the online video store, and might well be merging the current Apple TV and the Mac mini into a more unified model serving its interest for the online movie market. So, at the end, Apple might have two solution, either ATOMising the Mac mini to potentially re-branding it as the "Mac micro" and compete with entry-level PC models (unlikely as margin will be small), or drop the Mac mini and come up with a new Apple TV which will be a merger between the current model and the Mac mini.
