Just thought of a few more scrolling through my iPod...
Time - Pink Floyd - the guitar solo
Heroin - the Velvet Underground - when the tempo speeds up during various parts of the song
Ashes of American Flags - Wilco - can't really explain this one, but the ending lyrics and outro will give me chills if I haven't heard it in a really long time
That's it for now. If you want links to the songs I'll post them but most people have heard of the first two so I'm too lazy to copy & paste those haha.
EDIT; oh yeah I love that song too, although I've gotta say I like OK Computer far more than Pablo Honey. All great stuff though!