Well, I for one have done the "hack" that allows you to install a CableCARD tuner on any Vista/Win7 PC.
Well, first of all...I wouldn't call it illegal as it doesn't circument any DRM. Really, the BIOS lock and Product key (which doesn't have to be unique...they all work mulitple times...it is not there for DRM or anything...it merely identifies the original vendor) are only there for support reasons at the behest of CableLabs. It doesn't break DRM, so this whole thing seems to be fine with MS (it was announced on one of their own sites...TheGreenButton...and is still there months later!). Neither MS or CableLabs has done or said anything. It is unlikely that they could even do anything, as the whole hack loads before the OS anyway (it is a DOS bootshell basically). I'm actually thinking that the Bios/Key issue will just stop becoming a requirement soon in the future, anyway. That combo is the single biggest thing holding PC's back and I'm sure MS would prefer not to have it as Win7MC is a much stronger product with CableCARD support.
Was it hard to set up? No, not really. I'd use Win7RC, though. Do I get all the channels? No, but I get the ones I want. Is it worth it? To me, yes it is.
Supposedly, when Win7 comes out the "SDV adapter" (similar to a device used on Tivos via USB) will support the PC DCT as well. This is just a rumor, but it is believeable to me. Also, the DRM will be relaxed somewhat in the next DCT firmware (1.18 I guess)...namely ClearQAM channels won't be copy protected.
As for the DRM, here's what you can and cannot do. You CAN move it to another drive. You CAN back it up. You CANNOT play the shows except on the PC that recorded it. That's it, really.
I also have 2 ClearQAM tuners...and those do NOT get copy protected. I couldn't get the QAM and the CableCARD working in Vista...it was one or the other...but it was seamless in Win7. My only issue is that my cable company de-authorized all the HD channels days after I got it. After a couple hours of the Cable guy doing signal tests in vain...I called them myself and found that was the issue (they made a mistake).
Also, both versions of the CableCARD tuner are USB. Yes, even the internal ones...they are NOT PCI or PCI-E. The slot is there ONLY to physically support the card...it plugs into an internal USB header or a standard USB-B connector.