well component still looks better even at 480i (interlaced scan). and it is still considered medium-high def. however at 480p(progressive scan) it will look even better. from what i understand 480i scans things such as colors one at a time, yet in 480p is scans the colors all at once, therefore giving you even more of a clear picture and definition. the separation of colors into the 3 main colors of the spectrum isnt to add graphics so much as it is to add clarity and definition. so even at 480i component still murders composite. and some tv's that have component also have progressive scan ability. all of your lcd tvs will have progressive, however if you have a flat screen tube tv, then unless it is a edtv(extended definition) then it will not have progressive scan capability. but the difference between 480i and 480p is there but not huge.
