Lots of cool spots downtown:
-Check out LA Live (yeah it's touristy but who cares) and have a drink at The Ritz Carlton @ LA Live.
-Bars: Seven Grand, Edison
-Food: Wurstkuche, The Lazy Ox Canteen
Definitely hit up the Getty Center and/or Getty Villa (in Malibu). Two completely different experiences, both worth doing.
Very much agree with these recommendations. This guy knows LA and not just hollywood.
I have a feeling that a lot of people want to go to Hollywood when they go to LA...and thats all well and good, but it sort of blows. One night is all you need, and do the bar hopping thing. Don't even bother with sky bar or the standard. I'd say if you need hollywood, start down on La Cieniga and go to Bourdoir/STK (you can eat at STK). nearby is also the belmont. Go up to sunset if you must and see if there is anything good at the Roxy or the Whiskey. The viper room is also still fun sometimes but smaller. House of Blues is actually worth being on sunset for if there is someone you want to see. Still a shit show, but not as bad as the sky bar is saddle ranch.
Down a bit on melrose are a couple worth while places to grab a drink-El Guapo (they have beer pong) or, for more of a restuarant/bar is the Villiage Idiot.
DingDingDao also recommended Old town pasadena...but i dont know if i would. Its one thing to go there if you live in LA and have been everywhere else, but its not really worth the time otherwise. Instead, i'd say go to Santa Monica. You can check out 3rd street, walk down ocean and easily take a cab to Venice.
If you've never been to an observatory before, the Griffith Park Observatory is worth it.
Also, check out the Derby's show list and see if they have swing music on a night you're near there. People that really know how to swing dance are there and its fun to watch and drink and listen to the music even if the swing dancing isn't your thing.
Korean BBQ in koreatown is awesome. So is karaoke. (its better in koreatown than in little tokyo).
There are a couple really good pastrami places too. Langers and (my personal fave) Johnnies Pastrami on sepulveda. Ask for it with cole slaw in the sandwich. trust.
The south bay (hermosa/manhattan) is better than huntington. Newport is the best beach to the south, malibu's smaller beaches best to the north. That being said, its been freakin cold the past couple weeks (for us). Not really beach weather.
If you're into mountain biking or rock climbing there is a lot of good stuff in the area too.
EDIT- just realized i typed all that and the OP hasn't even responded in the thread since he started it. Oh well.