I find that Liquid Wand Gloss Summer Fling is MY perfect Nude shade. I'm Asian with light golden toned skin who somehow cannot wear copper or too brown shades. I find that when I want a lip with enough colour not to look washed out, enough shimmer to have some fun, and not too much of anything so it fights with a strong eye look, invariably reach for Summer Fling. It also seems to work with either cool or warm eye looks. I still haven't figured out how. I've just bought my second tube, one to have at my dresser and one to carry around!
Don't despair over birthday suit by the by. It has its uses. I find that mixed with damsel, it IS a lovely nude colour. And when I've done my makeup, peer in the mirror and think "oh dear the lip is too bright/candy/lil girl/pink/strong for work" I top up with a light sheer coat of B'day Suit and voila! The day is saved. =)