It depends on the games as to how much of a difference you'll notice. Not all Wii games support 480p, but for the ones that do, the only way you can take advantage of it is with the component cable.
In most cases, games that support 480p should look better using a component cable, but how much better is subjective.
Will I notice a big difference if I hook my Wii up with the component cable as aposed to the composite cable? I do not want to spend the money on the cable if it is not going to be a noticeable difference. This is for a 55" Sony Grand Vega Projection.

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