Down around Redondo Beach is nice too and is less expensive than Santa Monica.
LA is very different to here as there is no real city centre, but some clusters of bars and shopping areas. Most of it is sprawling though, hence the need for a car! The freeways are an eye-opener! eep! So much traffic!
The closest thing to a town centre (bars restaurants, shops together, in walking distance etc) would be in Santa Monica, Malibu, Pasadena, Redondo and Newport Beach. Hollywood is ok, but be careful what part you're staying in - some parts are very dodgy!!
Have a look at tripadvisor.com - it'll weed out some of the dodgier spots and hotels, which LA has plenty of!!!