It's important to note that except for "Triangler"
and a couple other songs from the Macross Frontier
soundtrack, Maaya Sakamoto and Yoko Kanno haven't worked together in several years. Sakamoto's voice is still nice on her recent albums, but the music lacks that certain something. So stick to the first four albums — Grapefruit
(2001), Shonen Alice
(2003) — if you want the good stuff.
EDIT: I see that Kanno did a couple tracks on each of Sakamoto's last two albums, but eh, it's not really the same. Yunagi Loop
(2005) was such a disappointment that I gave up.
Anyhow, other favorites besides "Triangler"…"Kiseki no Umi"
(from Record of Lodoss War
(from Wolf's Rain
)"Yakusoku wa Iranai"
)"Pocket wo Kara ni Shite"
And yes, all of their stuff together was this good. Basically, just go here
(their two "best" albums on YouTube, although "best" is relative in this case).