A friend of mine always has gorgeous looking lips. Her secret is Elizabeth Arden's Eight Hour Lip Protectant Stick. I've just bought one for myself in Blush. I'm really happy with it, particularly as I usually find lipstick really difficult to shop for.
This is how it looks on. It's a sheer lip tint. It's rich and creamy and feels like a balm. And, most importantly it has a lovely smell.
It's available in other colours, Blush is probably the most transparent of the range.