I love a wellmade trailer. It can encompass the feel of a movie or just briefly show you what it's about. Sometimes they are like a well made music video. Sometimes it simply kicks ass. The best trailer I've ever seen is this one from Kill Bill. It's the first trailer, if I remember correctly.

What's your favorite? Embedd it in the thread so I can partake in its awesomeness!

The original "The Matrix" trailer was the best.

@MarcioSMG - Awesome trailer! A bit too long, but still awesome :D

@Sguy78 - Unless you can find and post which one you mean, I can never be sure I got to see the right one.

The best movie trailer I have seen is the trailer for Red Eye. When I first saw the trailer, my initial reaction to the trailer's first minute was that it was a romantic comedy; however, that initial assumption changed after I saw more of the trailer. 

The trailer for Sin City is my second favorite. What I found most appealing was the use of the song "Cells" by The Servant. The feel of the song was congruous with the feel from the visuals. When the two were combined, it made for a superb trailer. I developed goosebumps when I first saw the trailer.

^ The Sin City one is awesome. I can see what you meant about the Red Eye one, but I don't like that one quite as much.

Any trailer of 300