2003OutKast - 'Hey Ya' and
Beyonce - 'Crazy In Love'

Very little needs to be said either of these, both with large amount of popular and critical backing for best single of the decade. Both enormously successful across the world and still sounding fresh when they turn up on the radio, despite the millions of plays already. Neither is particular ground-breaking or proved to be particularly influential musically but it's they aren't all that conventional for such mass appeal, certainly at the time 'Crazy In Love' wasn't receiving massive backing from Columbia until Jay-Z got involved. Both are just a brilliant example of finding the right formula and knocking it out of the park.
50 Cent - "In Da Club"
Before the above two records there was only one person being discussed this year, everyone had to have an opinion on Fiddy. I still can't quite tell how much of a knowing wink the video of him being assembled by committee is. He had the perfect back-story, which managed to be equal parts against the grain yet was still in part so clichéd that still managed to put it on the big screen in the same way
8 Mile was. As has already been mentioned, if nothing else there's always the frat-boy mantra of "Go shorty" which will no doubt out live us all.
Yeah Yeah Yeahs - "Maps"
Who'd have thought it? If you'd said to me around the time of earlier singles and EPs that YYYs would gain recognition for something other than being another arty-rock band from New York I'd have cocked an eyebrow. An actual minor hit on both sides of the Atlantic purely on the strengths of the video and Karen O's fearful and powerful vocal. It may not have seemed like it at the time and it's taken a few years of hindsight but did this song and the cult of Karen O, along with the switch away from beery lad-anthems in the UK to more arty, cool, fashion conscious indie music that has allowed a much larger proportion of a generation of young women to get into more rock based music. More on this next year.
Goldfrapp - 'Strict Machine'
I think it's unlikely I'd have included this one had I continued with this when I first started it. Now it seems surprising that
Black Cherry only made #19 in the album charts (it went on to go platinum) and that the band were criticised for "Ambulance chasing" by Pitchfork for moving into a more rhythmic based electronic style. That seems totally natural as the chillout wave they rode in on was dead barely while they were still touring
Felt Mountain. Looking back it's easy to pin Madonna's change of direction to the success of a song like this (Cue Oldfrapp gag). There's also little doubt that the continuing dominance of lists like BBC's Sound of 20xx by the likes of La Roux, Little Boots, Ellie Goulding, Mariana and The Diamonds in the girls corner as well as MGMT, Passion Pit, Hot Chip, Cut Copy all managing to get radio play in the UK on the basis of either sounding like this or a single that will turn up next year. As well it's worth considering the directions taking by Phoenix, Yeah Yeah Yeahs and Metric towards the end of the decade as well.
White Stripes- 'Seven Nation Army'
I nearly didn't include this but it's hard to ignore the moment they turned into the figurative elephant of the alternate music universe. With one of the most memorable riffs of the decade Jack and Meg broke through the barrier of the New Rock Revolution in a way that The Vines, The Hives, The Datsuns, BRMC and even The Strokes hadn't and never will. They (and in particular Jack) are the most important rock band of the 21st century and this is their most important and biggest moment. Both bands toured together this year and even supported The Rolling Stones, who tellingly only watched the Detroit band from the sidelines. The Strokes aren't ever going to be on The Simpsons are they. Nor are they going to be on the front cover of Mojo or Uncut in 15 years time every six months in the way that The White Stripes no doubt will.
Others from this year that I feel are important but not worth blurbingKelis - 'Milkshake' Slightly less gargantuan than those three at the top of this post but after European success at the start of the decade this playful single got her noticed at home. Boobies.
Black Eyed Peas - 'Where Is The Love' See first sentence above. While this is their best single in keeping with most of the massive hip-pop songs this year, it's the only one by the group that doesn't want me to fill my ears with cement.
t.A.T.u. - 'All The Things She Said' No-one fell for the back-story on this one, did they? Good work Russian Shapovalov!
Punjabi MC - 'Mudian To Bach Ke' The continuing globalisation of the music industy, aided by the internet continues at pace.
The Knife - 'Heartbeats' A better song but less immediate impact than 'Strict Machine' Similar influence though.