I couldn't find either of my favorite scenes on YouTube, but they are...
1) A Few Good Men...the scene where Tom Cruise is drunk and saying they shouldn't put Jessup on the stand:
"eeehhhhh! Time's up! What do we have for the losers, judge? Well, for our defendants, it's a life time at exotic Fort Leavenworth! And, for defense counsel Kaffee, that's right, it's a court martial! Yes, Johnny! After falsely accusing a highly decorated Marine officer of conspiracy and perjury, Lieutenant Kaffee will have a long and prosperous career teaching... typewriter maintenance at the Rocco Globbo School for Women! Thank you for playing "Should we or should we not listen to the advice of the galactically stupid!"
2) Shag The Movie...Carson and Buzz in the closet at the house in Myrtle Beach:
"You don't know me, you don't love me, you sure as all damn don't want to marry me, so why don't you leave me the hell alone?
I also love a bunch of scene from The American President, but the speech at the end is great:
http://www.youtube.com/watch?v=44R5BapEdYY