I'm with Sebrof and Theo on this one. The only relevant retail price is the current one. Everyone here assumes that retail prices only increase over time. I have seen retail prices of imported gear decline (sometimes significantly) when a change in distribution occurs. I don't think it would be appropriate to list the old retail price given that the current price is lower.
Retail?
When listing an item's new retail, should the price be the current retail, or the price of the item at the time it was purchased? If you know someone bought an item for $2,500, it is 3 years old, and the say the current price is $3,300 and are asking $2,200 - is this appropriate and honest or somewhat not?