I can probably help expand on Wayne's answer. I've spent some time with the HTPC/D-ILA combo, and I can say the DVD image created at the native panel resolution of 1360x1024 (1360x768) is incredible.
You're right in that the digital projectors all re-scaled HDTV to their native panel resolution. I was hoping the JVC allowed no re-scaling on 1280x720 material, but I was not able to figure out a way to achieve this; it rescaled both 720p and 1080i.
The hardware HDTV tuner cards from HiPix and AccessDTV do not yet offer D-ILA "pixel perfect" resolutions that would allow you to bypass the projector's internal scaler. They may be working on these now, but I was told by TeraLogic that developing custom output resolutions for the Janus chipset is actually quite involved.
Software HDTV applications, which have not yet been publicly released, will allow you to scale (OTA only) HDTV to "pixel perfect" resolutions that would allow you to scale HD with your PC's videocard and avoid the projector's scaler.
This comparison is one I am very anxious to make, but I've not yet been able to do so. When I have, I'll post some feedback here.
As an edit, if you have a fixed-pixel projector that has 800x600 or 1024x768 resolution, you can use the HiPix or AccessDTV to scale HD and avoid the projector's scaler. Maybe some LCD/DLP + HiPix/AccessDTV owners, who have also used the DTC-100 through their projector's scaler, could post their opinions on which looks better.
[This message has been edited by hifipj (edited 05-26-2001).]