well from my experience, composite is ok enough for an SD TV. it gets the job done and miles better than RF. S-Video will give you a crisper picture with better color separateion. the colors don't bleed as much across pixels. component is a whole lot better since the channels are now separated even more, so the picture is even more sharp and the colors tend to look brighter. (you have a 27" sony wega so this is as good as it gets for that TV) the only problem with better inputs on low resolution console is that you notice the space between the scan lines more. I noticed this while playing final fantasy 7 on my ps3 hooked up with hdmi on my 40 inch lcd. everything was sharp and clear but made the tech look really outdated.

s-vid on snes/genesis generation consoles look great. IMO its the goldilocks not too sharp.... not too blurry.