FWIW, there's generally two schools of thought.
Some guys like the light gear. 0-3 wt slow action gear. There's no real functional advantage, but the "feel" of a small light rod on a small stream has a certain appeal, and it allows 5-8" fish to show off as you can feel the fight better. The downside is that there's some tighter places you can't fish as effectively, but those that like this approach say the difference between 25 and 30 fish in a day is meaningless to them, and they'd rather enjoy the ones they do catch.
Others like heavier gear. 4 or 5 wt rods, fast action, perhaps overlined. Generally, these fish aren't line shy or drag shy, so "finesse" isn't really needed. The beafier setup and faster action will allow you to throw tighter loops through small windows and under overhanging branches and so forth. The downside is that you lose the ability to feel much of a fight out of little parr, because a short, stiff rod is kind of broomstickish.
Both agree on rod length. As long as you can get away with, but not longer. 🙂 Length is nice to lift line over currents, poke a rod into places, etc. But a long rod is unwieldy to walk around with, much less wave back and forth in thicker places. Generally speaking a 7 or 7 1/2 foot rod is a good jack of all trades brookie length. There are a few nasty rhododendron choked streams out there, though, where something even shorter is useful. There are also more open places where your regular 9 ft 5 wt is just fine.
For what it's worth, I fall in group #2 and take it to the extreme, as I've never considered the fight of a 7" fish to rank among my reasons to go brookie fishing. I use a medium-fast 4/5 wt rod and load it with 7 wt line, typically on 3x or 4x tippets (just small enough to fit through the eye of the hook). If a stream is more open than most and I expect some longer casting, I trade down to the other spool, loaded with 5 wt line, on the same rod.
Mine's a Cortland GRX. Don't think they make em anymore.
My next brookie rod will probably be:
TFO Lefty Kreh Professional Series - 7'6" 5 wt. Hard to find short 5 wts like this. I test casted it and it roll casts like a dream. About $160.
Other recommendations.
St. Croix Imperial - 7'6" 4 wt - love the Imperial, always have.
Orvis Clearwater - 7'6" 5 wt - I personally don't like the action on Clearwaters, but others may, and this setup fits the bill for the type of rod I like on small streams.
