I' m pretty sure the Mini Mac does *not* have the horsepower to playback 1080i content. I've got a 1.33 Ghz 12" Powerbook and as an experiment I attached it to my Panasonic PT-AE700U last night via the VGA connector (I don't have a DVI <-> HDMI adapter to connect digitally). I downloaded DisplayConfigX and shortly thereafter had my PB using the projector as a second display at 1280x720.
I then downloaded the 1080i 5 minute clip ot LOTR from the eff.org web-site and tried playing it using both Quicktime and VLC on the PJ. It was dropping at least 20% of the frames. So no go. You'll note that the specs on the 12" PB are very close to the Mini mac (same bus speed, same L2 cache, etc).
Now it is possible that the 1.42 Ghz mini mac which has a slighter faster CPU, plus the fact that it has (I think) a better video chip, and it would only be driving one display instead of two (I hadn't shut-off the internal display on my PB) would get the job done, but I'm doubtful.
I also downloaded a few 720p DivX trailers from http://www.divx.com/hd/
and tried those out. I'd say my PB was able to play at about 95-98% frame rate -- there were definitely dropped frames but it was not as bad.
So, what would I do? Well, I'd like the mini mac because I'm interested in having access to my music and photos in my HT *via iTunes and iPhoto*. So it might be worth it to me to spend the $750 just for that (1.42 Ghz mini mac + $100 superdrive + $50 bluetooth adapter). The EyeTV 500 is also an interesting accessory to add for an additional $300. Esp since it does QAM recording (though I want to see some more comments on how well that works). But what about playing that HD content that the mini mac doesn't have the horsepower for? Well, for $250 you could add the LinkPlayer2 and use that to play all your HD content, as well as handle upscaling of any DVD's you rip to the mac, you get DD decoding, etc.
So, for $750 + $300 + $250 = $1300 you've built yourself a fairly nice Mac based HTPC that has some unique advantages (for Mac users) over a PC based HTPC:
- QAM recording. I've read there are limited QAM recording options in the PC world and they don't work that well.
- iPhoto and iTunes access to your digital pictures/music library
- El Gato software for editing captured content, converting to mpeg4, etc.
- A lot easier to setup/manage than an HTPC (I would hope)
Now that same $1300 could also buy you a fairly nice PC to build either a Windows or Linux based HTPC. But that's going to take a lot more technical savvy than the Mac + EyeTV + LP2 combo.