If your budget can afford it, the Beverly Hilton is by far the best choice (rates are probably USD 250/night and up, though). With its recent refurbishment this is one of the best hotels in the US and has a great location. If you want to stay on the beach, it won't be at a Hilton and more expensive. The beach is great to visit for a few hours (maybe more in the case of Venice), but Beverly Hills is much better location for a hotel.