And in my mind, the most perfect pop song is Blues Traveler’s “Hook”. A great hook (haha), great voice, great lyrics, an awesome bridge with the best harmonica solo I’ve ever heard… Heck it even sings about what makes pop songs catchy and adds a level or two of irony as well. 
Lots of good choices already mentioned. I’ll try to mention songs that haven’t been listed. Pretty much impossible to limit it to just five songs in the last 25 years, though!
Ten favorite Canadian songs
The Pursuit of Happiness - I’m An Adult Now
Blue Rodeo - Try
Men Without Hats - The Safety Dance
Barenaked Ladies - Falling For The First Time
The Parachute Club - Rise Up
Delerium - Flowers Become Screens
Boys Brigade - Melody
The Boys Brigade - The Passion of Love
The Spoons - Romantic Traffic
Internation favorites
The Police - Every Breath You Take
Split Enz - I Got You
OMD - If You Leave
Level 42 - Running In The Family
New Order - Regret
Depech Mode - Enjoy The Silence
The Stone Roses - She Bangs The Drums
The New Pornographers - Letter From An Occupant
Marillion - Kayleigh
The Flaming Lips - Race for the Prize
Kula Shaker - Shower Your Love
The Postal Service - Such Great Heights
Most of my top choices have already been mentioned, but here are some honourable mentions:
Duran Duran - Save a Prayer
U2 - With or Without You
Erasure - A Little Respect
Madonna - Like a Prayer
REM - Losing My Religion
Dexy’s Midnight Runners - Come on Eileen!
Simply Red - If you don’t know me by now
No idea (the early 80s version) - It’s my party
Michael Learns to Rock - That’s why
Spandau Ballet - True
Beat that, pop-pickers!
Depeche Mode Master and Servant
Soft Cell Tainted Love
The Smiths This Charming Man
Elvis Costello Veronica
Killing Joke Love Like Blood
This question has now been definitively answered. You may carry on. 
What a great bunch of lists. I just made a mix disc with a few of the songs that some of you listed. Including:
Beat It by Michael Jackson
Bette Davis Eyes by Kim Carnes
Down Under by Men at Work
Sweet Dreams Eurythmics
I also included
Are Friends Electric by Gary Numan
Cradle of Love by Billy Idol
Other ones I love are Smells Like Teen Spirit by Nirvana. It’s fantastic single from one of the best albums from the 90’s.
I really like several songs by Duran Duran including Rio and Hungry like the Wolf and put Wild Boys on my mix disc.
And I think Hey Ya! by Outkast is one of the best singles of all time. I never get tired of hearing it.
Queen’s “Another One Bites the Dust” and Devo’s “Whip It” should really be on this list.
A new one:
Tide is High by Blondie.
Somebody to Love. Queen
Mint car. The cure.
Las Flores. Cafe Tacuba (It’s pop… in spanish, it’s also one of my favourite songs)
99 red ballons. Nena.
The caterpillar. The cure.
So many 80s songs… I’m going to try to make mine a little newer
“Do You Realize” - the Flaming Lips
“Red Dragon Tattoo” - Fountains of Wayne
“Can’t Get You Out of My Head” - Kylie Minogue
“Yeah!” - Usher feat. Little Jon and Ludacris
“Dragostea Din Tei” - O-Zone
Honorable Mention: “Somebody Told Me” - the Killers
I’m going to second the nominations for[ul]
[li]99 Luftballoons by Nena[/li][li]Girls Just Wanna Have Fun by Cindi Lauper[/li][li]Everybody Wants to Rule the World by Tears for Fears[/li][/ul]
For myself I’m going to also nominate: [ul]
[li]She Blinded Me With Science by Thomas Dolby[/li][li]Centerfold by The J. Giles Band[/li][/ul]
Yes, I don’t listen to much pop anymore. Why do you ask?
I wonder if it says anything about music in the last ten years that we’re sticking for the most part to stuff from the 80s and early 90s. Or if it says anything about us
For my part:
U2 - Pride (In the Name of Love)
Bon Jovi - You Give Love a Bad Name
Talking Heads - Once in a Lifetime
Prince - When Doves Cry
The Clash - Rock the Casbah
In large part, I think we’ve seen a lot less quality ‘pop’ in general recently - radio stations that used to play ‘pop’ are playing a lot of things that, to me at least, sound more like ‘hip-hop’ and ‘R and B’. Not that this is necessarily a bad thing, but who would’ve thought we’d ever look back at the 80s/early 90s as a golden age for pop music.
My favorite pop song list night be a little skewed since I don’t really like pop:
The Cure-Just Like Heaven
XTC-Dear God
The Smiths-Big Mouth Strikes Again
Berlin-The Metro
The Go Go’s-We Got The Beat
There’s a lot of other songs I thought of but ruled them out for being too Rock.
Well, heck, there goes my street cred. That should, of course, be Lil Jon.
God help me for saying this, but:
“MMMBop” by Hanson is one the best sounding pure pop songs ever.
I believe Brian Eno (who should know) said the best was “Soon” by My Blood Valentine.
Rock Me Amadeus - Falco
Several good choices. I’ve just lately begun to appreciate 80s pop. Most of the good stuff was never a hit.
5. Manic Monday: Bangles (Perhaps the most perfect pop song ever. Prince wrote it)
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Vacation: Go Gos
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My Sharona: Knack
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Too Shy: Kaja Goo Goo
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Pop Song 89: REM
Whooooo! One of the top pop songs sung evar !
Gotta second the 99 luft balloons song. Either by Nena or by Lustre.
Footloose has got to have made Kenny Loggins a Mountain Top Mansion somewhere.
And whatever the title is of the song that is so freakin’ catchy and I don’t know who sings it or when it came out:
**“Oh what a night. Late September back in '63. What a very special time for me. What a lady and what a night!” ** someone end my misery.
And now to put an earworm in your brainbox:
**Oh Mickey your so fine! Your so fine you blow my mind! Hey Mickey! ** by Toni Basil
[size=1]My work is done here.
[QUOTE=Hugh 3. My Sharona: Knack
[/QUOTE]
Almost. That was 1979.