I've got digital cable, a progressive scan DVD and an xbox. I want to view all of them in HDTV... does this mean that I need a TV with 3 component video inputs?
I am also considering buying an Onkyo HTIB (HT-767C) and this comes with a receiver capable of component video switching. Will this solve my problem?
Neither "Digital Cable" or a "Progressive Scan DVD" will give you High Definition picture quality. I'm not a big gamer, and without making a mistake on this one, I'll say that I'm not sure what you'll be looking at with the Xbox or PS-2. But, I doubt very much you'll be rendering 1080i or 720p with it either.
I can't comment on the Onkyo either other than the simplicity and best quality picture you'll get from those devices without limiting one or more of them to RCA inputs or S-Video. I'm sure it does a fine job in reference to utilizing Component Video via an "all component cabling" setup.
You'll need to add two more items to watch HDTV. And that is your HD decoder and your HD content. The choice of decoder is based on what subscription base you'll be using for your content. Cable? Satalite? OTA? Contact your provider and ask about the HD content they provide and what hardware they recommend to watch it. Programming is still quite new (as you probably already know) and you'll just have to wait it out before more channels and programming are available.
Not sure this helps...but, patience is the word for today for HDTV.