This statement will surley raise some ire...
"Long live Microsoft Ultimate TV!"
I bought my Microsoft/RCA Ultimate TV DVR 2.5 years ago. It has been great! I can record 2 shows at once from my Direct TV receiver and I upgraded the harddrive to 120 gig so that I have 90+ hours recording capacity. I no longer watch commercials!
I just added a 2nd HD to my DirecTivo. Very cool! It's also got 2 tuners in it (for recording 2 shows at the same time or recording 1 and watching a different one).
It's only $5/month above DirecTV costs. The cost is worth the benefits. I could rig something up with one of my Macs or PCs or something Linux (I'm a software developer). But I don't have time to spend meddling around and not getting it "quite right."
Yeah, I'm a Tivo (actually DirecTivo) evangelist, almost as much as I am a Mac evangelist.