To Fully enjoy your Full HD TV, use only Full HD devices like PS3 (for Full HD games & BD movies) or BD player (BD movies).

But that only is not enough, your source that you're playing must be in Full HD as well (HD Ready is enough actually)

In order to play the HD source, HDMI cable must be connected as HDMI brings lossless/uncompressed HD audio and video to your receiver and TV.

Astro is not a Full HD source. the quality is only DVD standard (worst), you can't see any HDMI or any digital output on the Astro decoder showing how outdated Astro is.

So, for Astro, CRT is still a better choice, HD TV won't do any good, but CRT is an old technology, (considering many people are more into HD nowadays) you wouldn't want to stuck with a nearly 90 year old technology don't you?

If you have a Blu-Ray player of course you need a Blu-Ray discs. If you're talking about format, maybe you meant Blu-Ray rip. The most common files for Blu-Ray rip is .MKV.