Wow, lot's of advice on almost no info.
How much do you have to spend?
Republican or Democrat?
Race can be a factor...
Where you work?
Whoever told you Santa Monica or Hancock Park is a little nutty. I can't think of may people/personality-wise where there would be a lot of 'cross-over' between those communities unless it has to do with religion.
Santa Monica is pretty jammy. it's a really weird cross section of old surfers and techie-yuppie advertising ppl. There are also the 'old-gard' who are the salt of what 'california living' is all about. It's very 'Liberal' and there's a lot of Yoga and alternative medicine. On the weekends it gets very busy and people aren't scared to walk around at all. Lot's of dogs. Basically the idyllic california, active, lifestyle. Very white not that much ethnic diversity.
Active, lefty, sunburnt, healthy-conscious, nouveau riche.
Hancock Park is HUGE, old, beautiful 2 story homes on tree lined streets. Like suburbia on steroids. I get the feeling it's a lot of 'old money'. West Hancock Park has a strong jewish community, with synagogs and old american cars, usually station wagons. East Hancock Park is slightly more asian with high end, shiny, luxury cars as it spills out into upper mid-Wilshire. South Hancock Park has some consulates and embassy and a small black contingent. Whenever I drive throught Hancock Park, the only people I ever see are the 'mow blow and grow' crew and the Hasidics on Saturday. Grand Old Hollywood.
Very diverse, serious, grand, old, central and the sound of sprinklers.
Hancock Park seems to be a little more happening lately as I've see some construction and it seems some homes are changing hands. So we'll see what happens.
Massive, sweeping, generalizations, but then again look how much time I saved you.