I guess I could qualify as both "a local and an experienced tourist". I grew up there and now visit often to see family, go to DLR, etc.
The best thing about HB is that there are very few condos, buildings, etc. on the sand side of Pacific Coast Highway (PCH), making IMO one of the best public and accessible beaches. PCH runs along the beach and is a great drive to appreciate the area. Breathe in that salt air!
State beach runs from the river at the Newport border to Beach Blvd., and city beach runs north from there. The city beach area around the pier is what most people think of when they think of Huntington Beach. The water is cold year-round; for example it's about 65 degrees right now. Parking is about $15 for the beachside lots.
The downtown area at the base of the pier has restaurants (cheap and upscale), shops, lots of locals and tourists, a surfing museum, etc. The pier has a Ruby's restaurant, surfers to watch, and some great views.
I don't need a hotel because I stay with family, but the Hilton and the Hyatt are both right across Pacific Coast Highway from the beach. The Hyatt is bigger, newer, and has a walkway over PCH to the beach. Predictably, more expensive too!

The Hilton is next to it (a little closer to downtown) and also very nice. There are other smaller motels north of downtown or inland up Beach Blvd.
For a listing of local events, check
this calendar. The vibe is casual and fun. There are usually people playing beach volleyball, surfing, a farmer's market on Fridays, etc.
PHXscuba