If you use a roller screen (as opposed to fixed) then, aside from a relatively small device either screwed to your ceiling or hidden in a coffee table - your 108" screen (or whatever) does not intrude in your room when it isn't in use - unlike your 50" (or whatever) Plasma (or even worse, RPTV, or worse still 128kg of 36 inch CRT) which is a huge grey/black 'thing' whether you are watching it or not.
Not mentioned often, but for me a major benefit (apart from the wow factor of filling your visual field) is the effect of having a wide sound stage match the visual stage.
Let me explain... Many people, myself included, have (had) a home theatre audio set up with front speakers widely spaced (often a necessity if they are not magnetically shielded) and a small CRT screen in the middle. Result: sounds impressive, but sound steering doesn't match the visual. I'm now watching a 6'6" wide image with the main speakers virtually touching each side of the screen. Result: wide soundfield as before, but the integration between sound and vision is now obvious and IMO so significant that I could never go back. In other words, when someone walks from left to right, the sound follows that person accurately and convincingly. Likewise with action scenes (e.g. the F18(?) down scene from Behind Enemy Lines).
Believe me, it really makes a difference. You can get accuracy of sound panning with a 50" plasma or a 36" CRT and magnetically shielded speakers by placing the speakers close to the screen, but the impact of the soundstage is considerably reduced due to the smaller physical width of the front three speakers. Nothing beats a large screen and correspondingly wide soundstage.
For me its the thought of being able to press pause and go to the bar you've just made out of MDF and get a beer without missing any of the film, also, maybe the thought of going for a pee withought missing any of the film, or is it the thought of being able to watch what you want when you want in the comfort of your own home, or maybe, yes, thats what it is, its the thought of watching a film on a really big screen with great sound and saying to yourself, ITS ALL MINEEEEEEEEEEEEE
I have gone in circles considering RPTV as part of my ultimate upgrade. In the end I have downsized my speakers, replaced my 32" tv with a smaller 28" with stand. The big tv was on a large wood AV unit (now in garage). This lowered the height of the tv immensly......why I hear you ask.....simple, now I can ceiling mount a sreen behind the TV so that I can have tv for daily veiwing and a PJ for DVDS
You see I came to the conclusion that a PJ like the ae500 will deliver far more smiles per pound than a similarly priced rptv! I can't wait to watch REAL home cinema on a widescreen format 7ft screen
Just need to squeeze a PJ/screen deal out of Benji_m now