While this January 24, 2009, does mark the exact 25 year mark of the release of the original Macintosh, I wonder if a new computer released on or around this date would actually be marketed as the "Twenty-fifth Anniversary Macintosh," as it would create some confusion in comparison to the release of the Twentieth Anniversary Macintosh, 12 years ago.
The confusion would be from Apple not calling the TAM, the "Twentieth Anniversary Apple Computer".
It was the one not accurately named.
A Twentyfifth Anniversary Macintosh would actually be the more accurate name of the two.
And anyone who remembers the TAM is probably enough of an apple geek that they know the difference in what each anniversary marked the beginning of, and would not be confused by it. John Q Public probably won't care.