[quote name='DreamSymphony']Component cables do offer the best picture and are the only way to get High Definition (including 480p) out of PS2 games and progressive scan for movies (on the newer ps2 models). However, very few ps2 games support even 480p, and only one or two support 1080i (one being GT4).[/QUOTE]
Technically, I think, "High Definition" begins at 720p. DVD-quality 480p is considered "Enhanced Definition", I believe. For a very brief time, you could buy "EDTV"s which of course would be a waste.
I think HDTVArcade.com has a good listing of ED/HD games, though I'm not sure how up to date it is]. But if you use component instead of RCA, even on non-ED-enhanced games, the picture is a little bit crisper and brighter and clearer. It's not a jawdropping improvement, but it is there. I wouldn't spend 30 bucks on cables, but the 7 or 8 I spent was worth it.