good advice above...
If your interest is casting first, I would start with a 7wt. Widely accepted by upper echelon casters as the most natural weight for men to cast.
if you want to match those fish you listed with just one rod, I would start with a 6wt accordingly - still get a wiggle from a bluegill but can land a steelhead with some effort.
Eventually you might consider an 8wt or a Spey rod for steelheading if that becomes a serious pursuit as it often will do.
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