Re: Best "style" steelhead/salmon line (singlehand)
If you're using a single handed rod, the best line for dry-fly and "greased line" (swung wet fly near the surface) salmon and steelhead fishing is a long belly weight forward floater. The weight forward line allows you to shoot for distance better than a DT, while the long rear taper allows for better roll casts and mends.
You don't want a spey or DT line. They will overload the rod when you try to cast with a lot of line out. You also don't want an aggressively front-loaded taper meant to turn over heavy flies like bass bugs and clousers, because salmon and steelhead flies aren't that heavy, and you lose a lot of mending control.
Most of the major manufacturers make a "salmon/steelhead" line like this. I have found that the SA Mastery XXD is similar and also a good choice. I don't think you can go wrong with any of the major brands and there isn't enough difference among them to cost you a fish on the water. When I need a new one I just look for whatever's on sale or clearance. If you look you may still find some old unsold stock out there without the welded front loop at a good price.
If you're also fishing weighted stuff, you might want a sink tip rather than a floater. Orvis makes one with only the front 4' weighted. I haven't used it myself, but it might be a good compromise between the need to go deep on the one hand and the need to roll cast and mend on the other.