To be honest, I do not consider the track Deconstruction to be among the best songs of the album. It is cool and it should definately be on the album as it is, but there are a lot of other songs on the album which I think are more awesome...
Addicted! has always been one of my all-time favourite tracks.
Ghost is plain beautiful, but I never felt this deep connection I did have with Ki.

Overall, I think Ki has had the largest impact on me, so that is were my vote went!

Ki. Always.

Ki... but only just above Ghost. Then Decon in 3rd and I can't stand Addicted so that's a fairly far behind fourth.

Addicted. Despite how I feel about Ki, I think it feels a bit insubstantial for the climax (despite how well it works). Decon is great, but there's some memorability lost in the massive flurry of notes, and I've never felt too strongly about the Ghost album as a whole. None of them are by any means bad, and it was all pretty close as they embody the themes throughout the albums really cleanly (Ki being about tension and release, Addicted being about fun bouncy grooves, yadah yadah yadah), but Addicted seems like the best song as a title track.

Ki. Why ? Because.

Addicted! - I'm, you know... It's the most memorable and has the best hooks and riffs (for me), and the one I sing along most to.
Followed by Ghost (beautiful and also good to sing), Deconstruction (fuck the dectractors, it's heavy & fun), and Ki (seven minutes of bliss that is last but in no way the least on the list).

Definitely Ki. Pretty much because of the way it starts in its calming guitars and lyrics. Plus, lets not forget that build-up throughout the song also .

Ki is absolutely perfect. That buildup is one of the best moments in his discography.
Next would be Deconstruction. The Vegimatarian Explosion (As my friends call it :p) is another of his best moments.
Third comes Addicted!, for its magical ability to get you pumped anytime, anywhere for anything.
Ghost is my least favorite, but it's still a great little song.

Ghost received my vote.

I'll echo the previous sentiments that all four are spectacular in their own right. I see each song as the purest thought of their respective albums. Ki provides that "Ah!" of relief, almost like an inspirational thought flowing into one's mind, late in the album. Addicted is stands out because it is the only one to occur at the album's beginning, like lacking the self-control to not eat dessert before the entree. Deconstruction feels to me as if an inevitable, insurmountable wall is finally hit and must be broken through in order to make it to the peaceful content of Ghost. And then Ghost is so simple and soft, and yet maintains that sing-song quality...the bass, the ambiance, the harmonies...so tasty.

I chose Decon because I think it encapsulates the entire point of the album on its own more than any of the other title songs...and it kicks ass. All of them are great though. Ghost is catchy as hell, even though I don't ever get the words right. "haba-daba-daba-da-moonlight...haba-daba-daba-da-home"

"haba-daba-daba-da-moonlight...haba-daba-daba-da-home"

This almost made me spit up my orange juice

Ki or Addicted, leaning towards Ki.

"haba-daba-daba-da-moonlight...haba-daba-daba-da-home"

HAHAHAHAHAha It's so true HAHA

Ki, that song ripped me an emotional asshole the first time I really payed attention to it! It might be my favorite track of all time, no joke.

"haba-daba-daba-da-moonlight...haba-daba-daba-da-home"

All of them are amazing for what the album represents, personally i would have to say Ki, Just atmosphere it brings, amazing.