what kind of bread do you serve with salmon?

Assume you mean smoked salmon? If so, what Pegeen said. But beware of the cellophane-packaged pumpernickel squares - they can be dry and tasteless as sawdust. Good, fresh dark pumpernickel is magic. Also, may be obvious, but a good bagel (not a crazy flavor - just sesame, poppy, onion or plain) is hard to beat with smoked salmon. I'm also partial to bialys - in fact, I had smoked salmon on a bialy at a brunch just this morning. Not available everywhere, but if available where you live, they're less bread-y than bagels these days - a very satisfying chew - a perfect platform for salmon and a smear.

Or "black bread" - the kind that comes in small squares - vs pumpernickel

And the spritz of lemon on top of it all

Sometimes chopped egg on top, too

Pumpernickel spread with cream cheese, then layered with thin-sliced salmon and sprinkled with drained capers and rough-diced red onion