"Equal" is a bit unfair to the 4th (Warriors) and 5th (Overlap) Openings. They stand much taller than the other 3, with Overlap being quite possibly the most awesome Opening for YGO in general.
And the dub theme gets even better in the second season. Behold the sheer epicness!
Someone set this to a montage. Watch it in all its glory here.
The theme that plays when Yugi first turns to Yami Yugi; it's called "Transformation", and it's epic.
If Duke Devlin's theme was turned into dialogue, this is what it'd be: "Hello, ladies. As you can see, I'm the absolute shiz, am I right? What's that? You want to challenge me? Bring it."
5Ds introduces a slew of hot blooded music that continues to pump you as you watch. The first track "Speed World" sets the standards by itself but then after that in episode 5, you get hit with Jack Atlas' battle theme which FAR exceeds our expectations.
Then Izayoi Aki shows up and we get blown back further.
We Ride to Survive deserves honorable mention, even though it didn't make it to being a theme song. This and the winner as stated above had a very close call in the contest to pick the theme song, with only one vote difference.
And if you thought that was awesome, you ain't seen nothing yet. In episode 109, something happened that doesn't happen often in Yu-Gi-Oh!: a vocal song played during an episode. This song is ''Clear Mind''. I must say, Endoh-san has just topped himself. Not only does this troper consider this to be 5d's best song, but also quite possibly the greatest vocal song in all of Yu-Gi-Oh! It's awesomeness is matched only by the Crowning Moment of Awesome that happens when it's first plays.
Pretty much all of the opening songs (Including surprisingly the dubbed openings).
For BGM, there's Jack, Aki, and Yusei's battle themes, the preview music and Clear Mind (Which is performed by the one and only Masaaki Endo who also did the 4th opening).
Speaking of Masaaki Endo, "Going My Way!!", the fifth opening, is on the fast track to being this as well.
This troper is extremely disappointed no one mentioned the first opening, "Kizuna"*
Lit. "Bonds"
, which is one of this troper's favorite anime opening themes.
Yakusoku no Melody the final insert song for 5D's brought this troper to tears hearing it for the first time.