That steel head trout that looks just like salmon smokes up nicely.
I actually prefer a good piece of Steelhead trout (Rainbow trout) but it lately it's been hard to come by. Ten years ago it was right there next to the salmon- always beautiful, and a buck or two cheaper. Now I rarely see it and it isn't cheaper than the least expensive specie of salmon, which is usually Atlantic farm-raised.
I know it isn't "popular" but I really like the Atlantic salmon. It has a nice velvety texture, a consistent flavor and the fat content makes it harder to overcook. I can't do $20/lb Wild Chinook or Coho.
In fact I've been less
pleased with wild salmon on a few occasions, but then it was cheaper than usual...
The Steelhead looks like it would do coldsmoking well.