Well you've picked a great time to come to LA. October is usually nice and mild. (Let's hope you avoid an early season winter storm.) Here are my thoughts . . .
Originally Posted by Little Dragon Kitty
I guess we want relatively un-crowded, beautiful views and sand, and nice walks, of course.. i have never seen an LA coastline before.. any good places for sunset watching, too?
Santa Monica Beach
This is the closest to the Bonaventure for straight distance, but it'll still take you some time. Depending upon time of day, it could take an hour. But it's more likely to take around 30 minutes if you can avoid traffic. (ie go at 3 in the morning!). Santa Monica has wide sandy beaches with great views of the curving Malibu coastline to the north. The pier is famous and third street promenade is right nearby for shopping and seeing local performers.
Venice Beach (is this joined to Santa Monica?)
This is the next beach south of Santa Monica. It's also a really nice beach, but the crowd is a little different. It's definitely the place for hippies and bodybuilders. The boardwalk has all kinds of funky stores to visit as well.
El Matador Beach
Don't know much about this one.
Zuma Beach
This is the one I used to go to growing up all the time. It's a south facing beach in Malibu, so it's going to be far away from where you're staying. It's a huge sandy beach that stretches forever. If you just want to sit on the beach, this is a great place, but there aren't any other diversions like shopping or boardwalks or anything.
Manhattan Beach
I haven't spent much time in Manhattan Beach, but I know a lot of people like it. I'll defer to people who know more about it.
Newport Beach
Newport is way south in Orange County, so it will be a hike for you from downtown. It's a really nice place in an upscale area.
Dockweiler Beach
This is the best because it's right under the departure path from LAX! As a proud airline dork, I highly recommend it.