One of my favorite drops is in Filter & The Crystal Method - (Can't you) Trip like I doWikipedia wrote:
http://en.wikipedia.org/wiki/Drop_(music)
The drop is the point in a track where a switch of rhythm or bassline occurs and usually follows a recognisable build section and break.
The buildup starts from 1:25 and drops at 1:50.
What're some other awesome ones?