This movie won the Oscar for Best Foreign Film, and (as I type) is #169 on IMDB's Top 250 Movies of all time. I agree: it's pretty darn good. Si usted no habla español, you'll have to read subtitles, but it's worth it.
Set in Argentina, it flips back and forth in time between the mid-1970s and (roughly) 2000. It centers on an investigator, Benjamin Esposito, who is obsessed with the brutal rape and murder of a beautiful newlywed. The 1970s segments show Young Esposito's initial investigation; his developing relationship with the widower; his hopeless love for his boss, Irene; his (very funny at times) interaction with his alcoholic partner Sandoval. The 2000 segments show Old Esposito's return to Buenos Aires after decades of exile, starting to write a novel about the events that still haunt him.
I especially enjoyed Ricardo Darín's performance as Esposito. I'd previously seen him in Nine Queens, and he's even better here. (Go figure: I've seen two Argentinian movies in my entire life and he's in both of them.)
I wish the movie had explained some things a bit better. Should you decide to watch, you might want to brush up a bit on your 1970s Argentine history first. I'm still not clear on a key plot point. Without spoilers: can anyone who's seen the movie tell me why it was necessary for him to leave, and not her?