I only knew this video from one of Weird Al’s “Al TV” shows:
“One… two… one, two, a one two three four - hold it… now!”
[sub]Warning: very 80’s.[/sub]
Pretty much every Ramones song has the count in, but I think my favourite is from their Happy Birthday dedication to CM Burns.
On a slightly more serious side, I love the slow count in on the Flying Burrito Brothers’ version of Dark End Of The Street.
(I don’t know what it means, but when I tried to find Youtube links for these, I could only find Spanish language versions of the Simpsons clips, and the Burritos song with the count in cut off from the beginning 
)
Seconding the Ramones. It’s not the beginning of the song, but I like KKK Took My Baby Away a lot.
Well, there’s always Major Tom (Coming Home) by Peter Schilling.
4, 3, 2, 1…
Earth below us,
something, something!
Floating, weightless,
something, something
Home!
Good song.
“Land of 1000 Dances” by Wilson Pickett (“One, two, THREE! [drum quickly followed by horn section] One, two, three! [drum quickly followed by horn section]”)
I came here to say Sheena Is a Punk Rocker.
Joe
Wasn’t there a song from the 80’s or 90’s that used a sample of Lawerence Welk counting in?
Something from King Cool.
Faux newscast intro to the video means we have to wait a few seconds for the countdown.
Raspberry Beret, Prince.
I was going to link to it on YouTube, but mysteriously it’s not there.
**Bad Company **- Can’t Get Enough. First track on their first album.
3 5 0 1 2 5 GO!
aka Warsaw-- Joy Division
Roadrunner by the Modern Lovers
ONE TWO THREE FOUR FIVE SIX SEVEN EIGHT!!
Listen to some live Springsteen shows. Let me know if you come across a song that DOESN’T have a countup. You won’t find one (two, three, four!).
Also, Peter Gabriel’s Games Without Frontiers has a countup that’s missing a number (a one, two…one, two, four).
“Do You Realize” by The Flaming Lips
Silp Kid by the Who starts out with a “1…2…3…4…5…6…7…8”. It’s the first song on the album The Who by Numbers.
Howzabout “Animate” from Rush and “When We Was Fab” by George Harrison.
James Brown’s “Funky Drummer” has two in the middle, one to tell the band when to lay out and one to tell them when to come back in. In between, Clyde does his thing.
And it’s a mother.
37 posts and no mention of “Uno… dos… tres… catorce!” from U2’s Vertigo?
A few others I can think of offhand:
“These 3 Sins” by Gomez
“Country Feedback” by REM
“Walkie-Talkie Man” by Steriogram
The Scrubs theme song, “Superman”
I know one of the versions I have of “Life In A Nutshell” by Barenaked Ladies has a count-in, but I’m thinking it’s a live one, rather than the album version.
It’s a countup, and part of the song, but it’s so fun that I have to mention the Violent Femmes’ “Kiss Off.”