Maui Tacos, for a chain, is really good. Also right across the street from the beach in Kihei is Alexander's Fish and Chips. It was great! Lots of great fresh fish that you order broiled or fried and stuck on top of french fries. You order at the counter, and then take outside. There are tables next to the place, but also across the street at the beach (Kalama?) park. Try the ono! Yum!! Right next to a funky shopping area, too.
For breakfast, also in Kihei, we were addicted to Cinnamon Roll Fair. Honey macadamia nut rolls with Kona coffee. Fantastic! Conviently located next down the way from a dive shop that rents snorkeling equipment by the week!
For upscale we loved Roy's (both of them!). That dark chocolate souffle is to die for!!!
Also, our favorite luau is the Old Lahaina Luau. Great fun, great location, great show, and the best part, great food!! Spend the extra for the hollowed out pineapple "cup". It's made for two, and filled to the brim with your favorite tropical drink! Ask for a "Tropical Itch" or a "Lava Flow." Free refills!! Be careful!!
One of our most memorable meals though was packing a lunch and eating in Haleakala crater. Amazing!!
Enjoy your trip!! I am envious!