If all you want is a well-made cable you can get those from Blue Jeans Cables, Audioquest or even Monster. However, there are a couple of options to using the headphone jack you should consider if you want to get the best out of the iPod.
An iPod dock with a line-out jack would bypass the internal amplifier of the iPod, letting you plug the 3.5mm stereo mini to RCA cable into the dock and then to your amp. There are lots of docks available but you can pick up a genuine Apple brand dock on ebay for less than $10 and be in business.
You'd get even better sound using one of the docks that take the digital signal from the iPod, bypassing both the internal amp and internal DAC. Onkyo, Cambridge Audio, Wadia and others make them at various price levels. One I've heard highly recommended is the Pure i20, one of the least expensive of the digital docks at around $90.
An iPod dock with a line-out jack would bypass the internal amplifier of the iPod, letting you plug the 3.5mm stereo mini to RCA cable into the dock and then to your amp. There are lots of docks available but you can pick up a genuine Apple brand dock on ebay for less than $10 and be in business.
You'd get even better sound using one of the docks that take the digital signal from the iPod, bypassing both the internal amp and internal DAC. Onkyo, Cambridge Audio, Wadia and others make them at various price levels. One I've heard highly recommended is the Pure i20, one of the least expensive of the digital docks at around $90.