Simple rules:
Track is predominantly vocal and the intro is at least 30 seconds long before any singing starts.

1960s - 'Tin Soldier', this brilliant intro from the Small Faces was featured last Friday.

1970s - I was really spoilt for choice during this decade, but I've gone for :- 

From 1971, a song inspired by the electronic music of Terry Riley this is The Who with the 1:08 lead in to 'Baba O'Riley' > I really like the visuals in this video too

There's many honourable mentions for the 70s >>> 'Question' The Moody Blues; Status Quo 'Down, Down'; 'Pretty Vacant' by The Sex Pistols; Faces 'Stay With Me'; and naturally 'Hotel California' and Lynyrd Skynyrd's 'Freebird'. 

1980s - Most versions of this track have at least a 30 second intro, though some recordings do vary a bit. From 1987 comes Guns N' Roses and 'Sweet Child o' Mine' >

Honourable mentions for the 80s are >>> Hall & Oates 'Maneater'; Europa 'Final Countdown'; Flock of Seagulls 'Space Age Love Song'.

> more tomorrow pop pickers...