I think it have to be in fly high. Especially the verses. Also the MARIAs in the end of M.

:yes She sounded so good in those two albums.
I forgot to mention Because of You and Memorial Address. Like xiaou already said, I love that desperate voice Ayu had in Memorial Address and then she sounded so angry and angsty in Because of You....I feel like crying.

i'm not sure if its my fave, but pride is waaaaay up there for me.

Theme of a-nation '03
Peaceful, strong, and just a little sad. Nothing can top the vocals in this song. Her best vocal performance ever, not a single annoying thing about it, even the "la la la" part at the end. A beautiful little song with amazing vocals.

Runner Ups:

Liar
Why does everyone hate this song and her vocal performance in it? I think it's amazing, one of her best. So much emotion in the chorus, I can't help but feel that she really is turning her back on love in that song (Check the translation).

Key~eternal tie ver.~
The small amount of instruments really goes well with Ayumi's soothing voice in this song. Once again, I can't find any flaws in her singing this time around and the final chorus is breathtaking.

SURREAL
All I can say about this song is wow. Some might find her singing to be a little annoying in this track, but I think it's a little raw and very beautiful. The bridge is absolutely stunning. She sings low, she sings high, it's just a great classic Ayumi sound.

ANGEL'S SONG
One of the few songs where I think Ayumi sounds like she's really enjoying herself without sounding annoying. The lyrics are so uplifting, and I adore the way she stops to say, "Kimi no se ni tenshi no hane wo mita". The verses sound better than the choruses, but it's got awesome vocals throughout.

- Far away
- Daybreak
- I am...
- Who...
- Close to you
- Free & Easy

@BANFAN: I also enjoyed her singing preformance in Key (the whole song was like whoa :) )

Memorial address, Moments, & teddy bear :yes

end roll (Stadium Tour 2002)

I agree with whoever says Forgiveness eheh (this one time i boosted the volume on a surround sound system and almost messed up my ears xDDD it was worth it)

Close to you

Ah, it's so underrated! Forget 'Dearest' and 'Voyage', her vocals compliment the arrangement so well in this song. Perfect winter love song. Her vocals bring so much warmth.

Others:

SCAR
WE WISH
Sotsugyoushashin
End roll (A BEST ver.)
Liar
Bold & Delicious
SURREAL

^^ I agree about "Close to you". Her voice is very soothing and peaceful.

A Song for XX
Key ~eternal tie ver.~
Memorial Address
alterna
Who...

i love her voice in SURREAL and immature. besides, yeah...Moments,nice voice!