First of all, if you have a shit TV you won't notice the
big difference. Even if it's an HDTV, if it's a rear projection older HDTV capable of only 1080i, most likely you won't see the difference because those TVs bleed so badly, the image is blurred resulting in a less than HD appearance. If you notice any difference, it will be extremely minimal.
If you have something smaller than a 32 or 26" LCD you will probably only see a minor, negligible difference.
If you have up to a 37" screen, 720p/1080i will look nice. If you have up to a 42" 720p/1080i will look good, but 1080p will look slightly better. If you have a 47"+, 1080p Blu-Rays will look as they should. 1920x1080 native resolution compared to DVDs 720x480 max resolution.
http://www.somethingnewweddingvideos.com/images/blu_ray_vs_dvd_screen.jpghttp://www.silver-ware.net/movies/potc1unf.pngMake sure you maximize the images in your browser to FULL RESOLUTION, something I think you don't understand.
The truth is for little TVs, yes you don't need the higher resolution. For larger TVs, you do. I'm guessing you're still rockin' one of these: