A good choice is long sliced, farmed Scottish salmon and the best to my mind should have a good depth of smoke, a dryish texture with minimal unpleasant oiliness. It’s cut closer to the skin, so the fat is more obvious.
For something special choose wild Pacific sockeye salmon, it’s dense and dry and ‘D-cut’ in short slices. For me though, it has to be smoked salmon from traditional Kosher smoker Goldstein.
If buying vac-packed smoked salmon open 15 mins before serving to allow the salmon to breathe.