Make sure to post the WORST as well.

The Best: Don't Forget About Us
The Worst: Many options but.. "S.O.S"/"Check On It "

best - eithers HDP or PG
worst - Taylor Hicks

Mariah.

Best:For whatever reason I love Grillz
Worst: Bad Day

DFAU wasn't a #1 this year. It was the last #1 of 2005.

Best: Promiscuous, Hips Don't Lie and So Sick
Worst: Taylor Hicks, Daniel Powder and James Blunt

Worst : Temperature

Did Mariah hit the # 1 position with
Don't Forget About Us??

It was on number one for TWO weeks- December 31 & January 7 week . So It was the last number one in 2005 ,and the first number one in 2006.

I think that's promiscuous
the worst is Laffy taffy-D4L

best: check on it, hdl, promiscuous
worst: bad day, do i make u proud

Best: Promiscious
Worst: Bad Day

from best to worst:

Bad Day - Daniel Powter
You're Beautiful- James blunt
Promiscuous - Nelly ft.Timbaland
S.O.S - Rihanna
Hips Don't Lie - Shakira ft. Wycleaf Jean
London Bridge - Fergie
Temperature - Sean Paul
Check On It - Beyonce
So Sick - Ne-Yo
Don't Forget About Us - Mariah Carey
Ridin' - Chamillionaire ft. Krayzie Bone
Do I Make you Proud - Taylor Hicks
Grillz - Nelly
Laffy Taffy - D4L

Best: Nelly Furtado - Promiscuous
Worst: D4L - Laffy Taffy

Best: Promiscuous, Hips Don' Lie, S.O.S.
Worst: Laffy Taffy

Best: Promiscuous
Worst: Ridin'

Fergie - London London London

Best - Promiscuous
Worst - Laffy Taffy (this actually went #1????)

The Best In my opinion is So Sick unless Sexy Love hits #1
The worst is London Bridge, London,London. And the worst isn't Ridin. Ridin was one of the best songs of the year because that song was one of the songs that you liked already when you first heard it and he (Chamillionaire) did not cuss in that song which was amazing.
Best songs of 2006
1. NE-YO - So Sick
2. Chamillionaire f Krayzie Bone - Ridin
3. Nelly Furtado f Timbaland - Promicuous
4. Shakira - Hips Don't Lie
5. Sean Paul - Temperature
6. Daniel Powter - Bad Day
7. Rihanna - S.O.S.
8. Nelly - Grillz
Worst #1 song of 2006
1. London Bridge
2. Laffy Taffy
3. Check On It
4. You're Beautiful
5. Do I Make You Proud

BEST: "Bad Day" Daniel Powter
WORST: "Laffy Taffy" D4L

How the hell did I miss We Belong Together 2 getting to #1?

Best - SOS
Worst - Don't Forget About Us, Bad Day, Check On It, Grillz, You're Beautiful, Do I Make You Proud. In any order, rilly.

I don't think that you can make Grillz one of the best songs while considering Check on it one of the worst songs. Check on it was much more better than Grillz The others are fine