Living in Santa Ana?
Okay, let me give you the counter to what many in here (and in most of OC) are saying. I moved to orange county 2.5 years ago, from Brooklyn.
I've lived in Huntington Beach, Irvine, Costa Mesa, and for the last year, Santa Ana. Santa Ana is by far my favorite part of the OC.
Everywhere else is "boring". Santa Ana has a thriving music and arts scene (which I am a part of). There are a ton of incredible young musicians coming out of the arts high school, there's an active street art scene, and there are plenty of galleries, concerts, etc. Lots of bars and restaurants downtown. There's a TON going on, and the city feels vibrant. Most of the rest of OC feels . . . crowded yet empty at the same time.
There are admittedly less desirable areas of Santa Ana, and yes - there are homeless people. To the guy that commented on bike theft . . . dude, I biked in NYC. If your shit gets stolen, it's because you didn't secure it well enough. Buy locking axels, get a Kryptonite NYC U-lock, and make sure your seat is chained/locked too. Yes, it's shitty that people steal bikes. But as long as you take precautions and make your bike harder to steal than the next guy's, you're fine (bike theft is common in NYC, Austin, and other areas - not just Santa Ana).
The people are way cooler and nicer and more community focused than elsewhere I've lived in the OC. Honestly, Santa Ana gave me hope for this area of California.
People who live in Costa Mesa think it's a terrible idea because they are afraid of people who are different than them. People who are hispanic. People who are homeless. People who are in a lower socio-economic class. many of the beach cities tend to skew upper-middle class, white, and conservative. you have lots of sheltered people who have lived like that their entire lives. And, to be fair to them, Santa Ana used to be a lot worse. That's what I've heard. But it's a city on the rise, and it's a city that actually has its own culture - which most of the other cities in the area can't say (consumerism doesn't count as culture, sorry, and "beach culture" is not unique to a place or its people, just the environment).
Again, I've lived and hung out in areas of Brooklyn that are far sketchier than anything you'll find in Santa Ana - and the worst that's happened to me was getting a bike seat and bike lights stolen. My only advice for housing would be to live above 1st Street.
Take the haters' opinions with a grain of salt. Come check the area out for yourself. Swing by The Coollab Project to meet a bunch of the artists and musicians that live in the area, and talk to people who actually live here. It's a welcoming bunch.