Hi Dinah!  I've eaten geoduck all the my life - it's great!  I've just recently adapted to eating it raw - very thinly sliced, sashimi style.  It's a major Japanese delicacy.  Japanese restaurants also do a wonderful job cooking it in some buttery sauce. 

Here's a fairly elegant photo of geoduck being served over ice.  You'd dip it in some soy sauce...it's a bit chewy, just ever-slightly crunchy and mild in flavor.   

Dinah, I have dug these quite a few times as well as cleaned and cooked them, however never eaten them!  We lived in a house several years ago right on the water near Vaughn and everytime we had the chance, we would dig and had family visit also to help because it is quite an ordeal to dig these monsters!  If anybody has ever cleaned a razor clam, these are MUCH easier, boil in water for a few seconds, transfer to cold water to pop off the shell and peel off the outer layer of skin on the neck then run water over to clean all of the sand out.  Once cleaned, you can slice up the body for clam strips and grind up the neck for clam chowder.  I have been told they are a bit sweeter than a razor clam.  About a year ago, it was featured on TV on "Dirty Jobs" right in Gig Harbor but the way they dug them was the industrial way, the easy way, not the true dig.  If you like clams you will love these, my husband does!!!!

Dinah, Can't believe you'd recommend a food you haven't eaten yourself!  That's as bad as saying you don't like something you have never tasted.

Anyway, your positive recommendation for geoducks is on the money.  My wife and I dig them our ourselves and eat them as sashmi or batter fried, depending on the part of the clam.  There's a good video on YouTube from Top Chef.  They are delicious.

As for the looks, (elephant trunk is a euphanism if I ever heard one) well, there are many, many things people would not eat if they saw them a naturiel.