Ayumi's the only one I can think of where I like nearly every song...... Even as much as I love Kumi, there are a lot of her songs I don't like. Hikaru....I used to like nearly every song from her, from her first three albums (four, if you count EXODUS). But, like with HEART STATION....I only like a few songs on there, and not that much.
Hm. Actually, I really like all but a few songs on every sweetbox album (with Jade, hah :X). It's weird, I'm not super-big on really poppy stuff like them and Ayu, yet I love their discographies most.