Just noticing the thread and can't sleep. Long list, but worthwhile movies from my lifetime!! I know some won awards or were recognized, but I feel like none of these got the wider appeal that they deserved and if you haven't seen anything here, it's a worthwhile list to explore!

Boyhood - This is in indie theatres now and is an amazing movie. Chronicles a boy growing up and was actually filmed over 12 years with same actors. Linklater is a genius.
Tape
Before Sunset - these last two are two more Richard Linklater films that are shot in realtime. More fascinating pieces of art with a style different than you've seen before.
Primer - Saw this mentioned earlier and I'm glad. GREAT movie and mindbender. Will give you headaches.
Mud - M McCaugnahey's best role in my opinion. Great southern gothic type piece with literary undertones.
Beasts of the Southern Wild - Another great southern film focusing on life in rural Louisiana around a hurricane. Pretty powerful.
All the Real Girls - David Gordon Green film from back when he was doing serious work. Similar in style to the last two in that it's an art-style southern film. You'll recognize some faces in this one!
Original "Old Boy" - this is in subtitles and probably 10 years old now, but it is fantastic. Best revenge movie ever made.
Three Kings - this one was directed by David Russell and saw national appeal but is largely forgotten. Eye opening film on war and a gripping piece. Features Clooney + Wahlberg
Moonrise Kingdom - this is my favorite of the Wes Anderson films. Great performances all around. Rushmore and Budapest round out his top 3.

More

Her - this saw mainstream success but was one of the most original movies Ive ever seen and was thoroughly enjoyable. Watch it if you havent
Midnight in Paris - Owen Wilson movie set in France from a few years ago. Vibrant film with a lot of life.
Curious Case of Benjamin Button - Practically Forest Gump 2 with different characters. Still highly enjoyable, though long
Junebug - I seem to like movies that explore the southern way of life, but this was another great one. Amy Adams bursts on to the scene in this one.
Scent of a Woman - Hoooo haahh!