Yes there is a difference, but a noticeable one probably not. In real life i believe only things safety related should be a MUST for copper or silver, such as the grounds on a hot tub or something like that. of course all grounds in a house should be copper too lol. here is a list i dug up of conductors from best to worst. Funny how concrete makes the list.
# silver
# copper
# gold
# aluminum
# iron
# steel
# brass
# bronze
# mercury
# graphite
# dirty water
# concrete