As long as: however wide the image originally was, that's the shape it is on my TV, regardless of how much letterboxing/windowboxing has to be done, then I'm happy.
Like it or not, we live in a multi-aspect ratio universe, so whatever shape you choose for a TV, not all films or programmes will fit. Personnaly, 16:9 seems to be a good compromise between a natural image shape, and (more importantly) a good halfway-point between 1.33:1 and 2.35:1, while magically being pretty much identical to the near 50% of movies shot 1.85:1.
As for the wider question of "if TV could be redesigned what would you change?" then where do you start? I could rant on all day about wanting HD, mandatory progressive scan, poor remote design (eg. interactive button not red), WSS standards, PAL/NTSC differences and framerate speedup etc etc.