Currently have 1333 songs in iPod, so I'll list just my favorites
Ayu's all studio albums + acoustic orchestra songs (from ayu-mi-xs and singles)
Utada Hikaru's albums First Love, Distance, Exodus, DEEP RIVER + Fly me to the moon, Come Back to me, Dareka no Negai ga Kanau Koro, COLORS
Koda Kumi's singles BUT/Aisho, FREAKY, MOON, 4 hot wave, 3 SPLASH, Trust Your Love
Vanessa-Mae's Subject to Change & The Violin Player
Anime songs/soundtracks: Higurashi no naku koro ni, Umineko, Sayonara Zetsubou Sensei, K-ON!, Code Geass, Lucky Star, Suzumiya Haruhi no Yuutsu, Death Note, Gundam SEED, Jigoku Shoujo
Tamura Yukari's albums True Romance, Hana-furi Tsukiyo to Koi-youbi, Izayoi no Tsuki, Canaria no Koi + Little wish single
Shikata Akiko's albums Harmonia, Navigatoria + Umineko no naku koro ni single
And many many more XD