Old school doesn't mean any specific shit. it just means old shit. it is 2013. Most young hip hop heads today were 5-10 years old in 2000. so, for the sake of the thread, keep the Hip Hop to pre-2000.
Ice T - Colors
http://youtu.be/LI8Zx_QvNVU
This song came out 20 YEARS ago. If that is not old school, nothing is.
Snoop Dogg - Murder Was The Case
http://youtu.be/LC2OpFMBReg
Public Enemy - Shut 'Em Down
http://youtu.be/LB4D-GbQ9A4
Grandmaster Melle Mel and the Furious Five - Step Off
http://youtu.be/-_g7CZJMnJA
DJ Kool - Let Me Clear My Throat
http://youtu.be/54yIMKjG048
Doug E Fresh and Slick Rick - The Show
http://youtu.be/bDkqz5C62SM