Los Angeles: Transportation in L.A.- pro/ con a car rental
Yes renting a car in LA is very helpful to see the city. If you're going short distances both Lyft and Uber are great apps for getting around easily. For renting a car this app is great http://www.skurt.co/
Los Angeles: Recommendations for place to stay in Santa Monica
Depends on your budget - there are several expensive hotels on Ocean Ave. that I'm sure you've come across in your search - Loews Santa Monica Beach Hotel, Viceroy Santa Monica, Shutters On the Beach, Hotel...