I use my pc. I do have a real sound system hooked up to the soundcard, so I can set it louder and get better quality.
My screen is only 17¨. The last was 19, but it was a 19 incher TUBE which weighed about 50 lbs and was too big to fit on the desk. this one is a light thin flatscreen on a pod.
Nothing special. I don´t think superluxurious home entertainment systems are necessary. You can always get a bigger screen, but It will not make your DVD´s more detailed. If I´d buy stuff now, I´d probably get a 19 inch flatscreen and make sure the system plays those new high definition DVD´s.
Better screen quality is more interesting than bigger screens. you just end up sitting further away from the screen. Not worth it to me.