A Happy Kristen and In-Love Vanessa Rock Vanity Fair Party

Hot Hollywood makes stops at Sunset Towers last night

While L.A. recovers from its Oscar hangover today, time to dish on how some of the hottest stars celebrated Hollywood's biggest night:

The Vanity Fair party at Sunset Tower, tho still recession-ized and catered by In-N-Out, was the big soiree of the night, bringing out the likes of Sean Penn, Sandra Bullock, Jennifer Lopez, Natalie Portman, Gabourey Sidibe, Ryan Phillippe, Abbie Cornish, Zac Efron, Vanessa Hudgens, Taylor Lautner and Kristen Stewart…just to name a few.

So how were some of our fave delish babes acting inside the exclusive shindig?

First off, it's safe to say recent exes Abbie and Ryan didn't exactly kiss and make up. Yeah, hardly.

"They really didn't come near each other all night," says one of our inside party sources. "But they both looked like they were having a good time. Separately, of course."

One honey who was all smiles was our fave gal, Kristen Stewart.

"She looked genuinely happy for the brief time she was there," spills our eyes. "She was smiling the whole night and hung out with Taylor inside for part of the time."

Uh oh…we can see the tabloid headlines now: "Kristen and Taylor's Steamy Oscar Night!"

Hardly, sweethearts. Dishes our source:

"They looked like great friends laughing and hanging out with the other celeb guests. It wasn't flirty or anything."

No duh. But since Robert Pattinson wasn't able to make it to the Oscars (he's currently filming Bel Ami) Taylor was K.Stew's platonic date for the night.

A couple seriously together, though, was Zac Efron and Vanessa Hudgens.

"Zac never left her side," we're told. Even though Z.E. made a pit stop at the Governor's Ball while Vanessa showed up to Vanity Fair solo, she came back out and snapped pics with her BF. Presh! Still, don't think these two are gonna last.

It was def a couplefest inside. Sandy held onto her Oscar and her hubby equally tight, Katy Perry finally joined Russell Brand at this Oscar shindig, and a very pregnant Amy Adams sat down most of the night with her hubby.

One dude very single, though: Sean Penn.

"He seemed to be talking with a new pretty girl every time I saw him," says our insider. For a guy who may have had an altercation with Hurt Locker producer Greg Shapiro backstage at the Oscars (Shapiro is dating Penn's ex Robin Wright), we're told he looked like he was happy and was having fun.

So…best dressed of the night? We're loving young Hollywood right now…we say Kristen, Vanessa and Natalie totally rocked it. Don't you think?