Since everybody forgot:
Honey and Clover (you can't really go wrong with the insert song and when you HEAR the BGM version of the OP/ED themes, you'd be sucked in)
Bokura Ga Ita and
Nana (anime version) is tied for 2nd place.
Macross Frontier and
True Tears is tied for my 3rd choice.
Other noteworthy mentions:
Bartender
Victorian Age Emma (Emma)
IGPX (immortal grand prix)
Saiunkoku Monogatari
And the rest of the anime found on my sig below (in green)
So do I win for the most non-rock soundtrack vote?