Gamakatsu #2 for the majority of winter fishing, frequently down to Gamakatsu #4 in low water. Occasionally I'll use Owners but see no tactical advantage to them. The last owners I bought, the eyelet's were not crimped all the way to the shank of the hook! Pissed me off and I haven't purchased any more!
I never use any hook larger than a #2 for steelhead unless I am actually springer fishing during the tail end of the winter run.