Sorry no McDonalds with a good view... probably thinking of Keahuou Wendy's, which went out of business. Supposedly Sam Choy is returning to town for a restaurant there... that ought to be good if it happens.
For a nice semi-upscale meal... Keei Cafe in Kealakekua (cash only, but if it were at a resort it'd be 2-3 times the price) and Jackie Ray's.
Burgers and more, try Splasher's. Just moved and expanded, I'm headed there tonight, will see if the menu's expanded too... one of the best breakfasts in the area. Don's Maitai Bar puts out a pretty good burger. I used to really like the big burger at Drysdale's, been a long time. I've heard the burger at Lava Java is good (the guy who basically put together Splasher's original menu helped put their "new" menu together when they expanded into more than a bakery he's a diver too, so it's gotta be good) but I haven't tried it. Heard Jackie Ray's burger is good.
Pizza... Kona Brewing Company. I'm also growing fond of Pizzeria Zachinni, different pizza's you'll either like 'em or hate 'em. I was ambivalent at first, now I kind of like them. Lava Java and newly opened Humpy's Alehouse also offer stone oven pizzas, I've yet to try either.
Beer... Kona Brewing Company. Humpy's Alehouse (orignally in Anchorage) just opened and has 36 beers on tap. Haven't eaten there enough to know if I can recommend it as a restaurant.
Drinks with a view... Don's Maitai Bar at the Royal Kona. Sure it's in a hotel, but a lot of locals go there. Good burgers too.
Interesting food... Rapa Nui. Owners from New Zealand I believe, serve food that's sort of Pacific fusion, spiced and flavorful, relatively inexpensive.
Plate lunch. People still rave about Big Island Grill, haven't been there in years. Pine Trees Cafe is pretty good. I hear good things about Tante's, especially if you want to try some Phillipino food. If heading through Waimea, Hawaiian Style Cafe is the best deal on the Big Ilsland - big servings.
Italian... I hear good things about Mi's in Kealakekua.
Mexican... used to be bad in Kona. Habanero's in Keauhou is interesting, I hear they're taking over the old Tres Hombres location (above Alii drive just up from the Royal Kona resort) for a sit down place. There's a place across from Sandwich Isle divers that is authentic as you can get
I'm sure there's lots more.