Whatever you do, get a dock that bypasses the iPod's terrible internal DAC so that you are streaming the digital files to an external DAC (then into the amp) or a DAC built into the amp. If money is tight, you might want to look at integrated amps that have a built in DAC. Practically anything will sound better than the output from the 3.5 mm headphone jack on the iPod straight into an amp (whether you are using a generic cable, one made by Russ Andrews or one made by Santa!)
Good luck!