The base speed has been bumped to 2.4 GHz, and default RAM to 2 GB. A 320 GB hard disk is now standard with option for 500 GB; The server model sports twin-500 GB drives (lacking the CD drive). Prices begin at $699 / £649 (!) / €799 for the standard model and $999 / £929 / €1'149 for the server model. A far cry from the days when the Mac Mini was a cheap PC (I paid £320 for my G4) but its success, even at these prices, is still grounded in its popularity as a quiet, well-balanced PC that has no real competitors of equal size for the power.(haters gonna hate)
Apple have increased the footprint of the device, whilst making the device shorter (the loss of the power brick however probably also makes for a lot less "real" volume). The previous generation Mac Mini was 2 inches tall (5 cm) and 6.5" square (16.5 cm). The new Mac Mini is 7.7 inches square (19.7.cm) at 1.4" tall (3.6cm)
The graphics chipset has been updated to a GeForce 320M, the newer version of the 9400M found in previous generations. Apple claim speed improvements of up to 2x with their usual vague charts. Expect benchmarks to start appearing as carputer users, modders and HTPC enthusiasts start getting their hands on the new models.
Speaking of which, the addition of an HDMI port seems almost un-Apple like as they have avoided on their main professional and consumer models.
It’s easy to connect Mac mini to the biggest screen in the house — your HDTV — courtesy of a built-in HDMI port. Plug in one HDMI cable and start enjoying content on your Mac mini in brilliant HD. Like films and TV programmes from iTunes, the Internet and your photo library. Like home movies, the Internet and your photo library. There’s also a handy control that lets you easily adjust the output on Mac mini to fill even the biggest HDTV screen. And when you just want to listen to music, you can play your entire iTunes collection through your home entertainment centre, or stream it to a set of speakers in any room via an AirPort Express Base Station.
However, the "main sell" of the new Mac Mini doesn't seem to be as a HTPC, but as a regular computer. Are Apple still cautious about the TV market? Just as with the Apple TV, the new Mac Mini screams HTPC, but Apple don't seem to be behind this idea with their full might, more "testing the waters" still. Their iTunes-centric view of media (as obvious from the quote above) is what's keeping Apple behind here in my opinion. Google's clear view to embrace the 'Web as the big, messy shopping mall of choice is more in tune with a large part of the consumer market. Not that the MacMini can't browse the web (it is after all a regular Mac OS X desktop machine), but that Apple see the web as the web, and HT functionality as iTunes--and ne'er the twain shall meet. Users in Europe want to use Spotify, and the Apple TV can't do that (out of the box, for the average user), where the Mac Mini could, and where iTunes doesn't compete.
What does this update imply for the Apple TV, I wonder. It's buried under the iPod section on the store, out of harms way.