From Pololu Valley Lookout
At the northern tip of the Big Island beyond the towns of Hawi and Kapaau, there is a beautiful view of Pololu Valley below with it's black sand beach. You can hike down to the beach but the path is rather steep and rocky so bring the right shoes and some water. If you're not a hiker, be assured that the views are wonderful even from the top. It was a beautiful sunny day when I took this picture and cars were lined up on both sides of the narrow road in addition to filling the small number of official parking spaces. The road actually ends here so you have no choice but to stop.
Waipio Valley Lookout
This photo is also from the northern end of the Big Island but to get to this lookout, you have to go through the town of Honokaa and follow the road until it deadends at the Waipio Valley Lookout. There is a small paved parking lot but on nice days like this, the parking lot is almost always full and cars are lined up on both sides of the road leading to the lookout. You can drive into the valley if you have a 4-wheel drive (the road is quite steep, at least at the start) or you can take a short walk down a paved path to the lookout where there are restrooms and a few picnic tables in a pavillion.
There is a lot of history to this area and there are still local families living down in the valley. This is also a place where taro is grown. Much of the land is privately owned by local families but you can still go down and explore as long as you keep out of the private areas.