I find fish to be a great partner for preserved lemons. Using them in some kind of sauce could make the salmon really interesting.

I often do a whole fish stuffed with shellfish. No need to do a sea bass, any whole fish with a nice white flesh works well.

http://events.nytimes.com/recipes/11473/2008/04/20/Baked-Sea-Bass-Stuffed-With-Shellfish/recipe.html

Something dramatic is always nice for a special occassion. You could cook a whole fish in salt crust. Simple to do, but a beautiful presentation, and it tastes delicious.

Gravalax, which would be cured salmon as opposed to en croute. Firm fleshed fish such as black code or scallops cooked in parchment (en papillote).