For walking I would go for a good quality waterproof shell with a fleece or duvet jacket underneath - gives you maximum flexibility.
That would be my suggestion too.
Something that is sometimes overlooked in these discussions is breathability. Many cheap jackets are totally waterproof (and warm linings can be cheap too), but jackets that are both waterproof
and highly breathable tend to be expensive.
Of course, not everyone wants or needs a jacket to be breathable. If you walk relatively slowly over shortish distances then sweat probably won't be an issue, whereas if you walk briskly over hills and long distances then a jacket's breathability might well be its most important feature. As an aside and IMHO, pit-zips might allow some ventilation, but they're also an indication that the jacket material isn't actually very breathable!
Another thing to consider is weight and pack-ability. Rain tends to start and stop, and it tends to be much colder on top of hills. Therefore, a jacket will often spend at least some of an outing being carried in a backpack. This is another reason why using a waterproof shell and separate fleece makes sense.
There are loads of good brands and we all have our preferences (or no preferences at all!). I'm a big fan of Rohan - my Vertex outer shell is the most breathable jacket I've owned and it's completely waterproof and beautifully made. For warmth, I wear a Rohan Microgrid fleece jacket underneath.