It's a simple answer really: next generation gaming consoles. Now that we know the Xbox 360 and the PlayStation 3 will both support full HDTV gaming, you can expect that HDTV sales will soar as we near the introduction of these consoles. If you think I'm off base, just take a look at the Elder Scrolls screen shot, courtesy of Paul Thurott's SuperSite for Windows. How could you pass up this scenery in high-def?
Of course, there are other reasons 2006 will be a highly succesful year for HDTV as well. Content providers continue to add high-def programming to their line-ups and that doesn't hurt either. Add in the regulatory pressures by the F.C.C. to provide digital programming signals and built-in HD tuners and you can see that HDTV is about to hit critical mass in 2006.