If — I say “if” — this trailer is a fair and accurate representation of Noah Baumbach‘s Greenberg (Focus Features, 3.12.10) then it’s going to be one of 2010’s smartest and most engaging films hands down, and why the hell didn’t they open it this year? (Too costly?) I wasn’t exactly pining for a dry, witty, low-key portrait of a 40ish L.A. loser, but this thing has me hooked. Focus should bring Greenberg to Sundance, where it’ll most assuredly kick ass.

It looks like Ben Stiller might have lucked into his best role ever, and possibly given his career-best performance…maybe. It looks like a breakthrough also for mumblecore veteran and Joe Swanberg colleague Greta Gerwig (Baghead, Hannah Takes The Stairs, Nights and Weekends). And Mark Duplass and Jennifer Jason Leigh are in it…great!

And Rhys Ifans…okay, I’m now even ready to forgive Ifans for playing that dreadful hippie creep in Enduring Love (’04), one of the most thoroughly repellent films of the 21st Century. (I realize, Roger Michel, that the opening sequence with the big helium balloon and the guy falling from it was amazing.)

The IMDB synopsis: “A New Yorker moves to Los Angeles in order to figure out his life while he housesits for his brother, and he soon sparks with his brother’s assistant.”

You can tell that Baumbach’s writing (he and Jason-Leigh share story credit) is spot-on, and that he (or they) may have tapped into something really primal and affecting this time around. Stiller’s character almost reminds me at times of my recently deceased brother, although my brother wasn’t as funny. (“I’d go further — I’d say ‘life is wasted on…people.'”)

If this isn’t a wank (an assemblage of the film’s best parts, and therefore a concealment of the fact that the rest of the film isn’t as good), Greenberg looks like the shit.

(The song is LCD Soundsystems’ “All My Friends.” Terrible news about drummer Jerry Fuchs, who died on 11.9 after falling five stories down an elevator shaft in Brooklyn.)