I just got my S-video cable for the Saturn ($20 on Ebay), and it's awesome. I have it hooked up to a 27 inch Sanyo flat screen tube TV, and the picture quality is incredible.
Come to think of it, my Saturn is now chock full of expensive peripherals. I have a $20 S-video cable, an official Sega backup RAM cart that sells for around $40, a modchip that sells for around $45, and two 3D "Nights" analog control pads that are worth around $15 each. I got lucky when I bought the Saturn as the two analog pads were included with the console for $30. Well worth it though. The Saturn is one of my favorite consoles, and the fighters, shooters, and Sega arcade ports are second to none. I wish I was into RPG's because there is quite a selection of those too.