I did a Kelly Blue Book search the other day. A used '04 XF 6-speed with 13k miles (my car) trades for $24k and change. An '04 SLK 320 trades for $34. Both cars lost about $10k in value the first year. So I would say $28k for a new year end '04 and $24k for a used one is not that far off, especially when the SLK's are in the same boat.

FYI: In order to purchase my XF last Dec I sold a 5 year old '98 Honda Prelude Sport Coupe with 28k miles on it. I paid $24k for it new and sold it to the dealer for $12k... that's what I call holding resale value. No matter what people on this forum think about Hondas, they do hold their resale value.