Hothouse Rehearsal Studios

Still the best rehearsal studio in LA and Orange County.

The owners are cool as fuck. The EQ was way better than any other rehearsal studio in that area.

I've been going here for a while now and basically this place is great.  All the info you'll need is on their website.  The staff is excellent.

AFFORDABLE
There are different sized rooms for different prices depending on what you need.  (personally I prefer the larger rooms) The downside to the smaller rooms is that sometimes you can hear the band playing in the small room right next to you.  That problem isn't there with the larger ones.  
Cash only

GREAT ATMOSPHERE
The staff is ALWAYS very accommodating and helpful with anything you need (even if it's just advice).  
There is plenty of parking.
Wifi is available.  
Multiple bathrooms.

HAS EVERYTHING YOU NEED
If your band needs something extra for practice, or if you've forgotten something at home, there is equipment you can rent/borrow/buy.  
There are drinks for sale

There are a lot of small, loud, terrible places to practice in the local OC/LA area and this is definitely NOT one of them.  If you choose to come here you should be very pleased.