I'd love to see the glitter wallpaper your girl has chosen! : D (something tells me it is pink...) I would use this in the shelves as it makes her happy, is possibly easier on the eye than a whole wall in the paper and easier to change later on. Romans are probably the best choice for the window dressing.

I too thought shutters would block out too much light, but the look when fitted is so lovely, and with wider size slats, the more light they let in. The pics below have small slats but its the same style of bay with shutters. Also don't have the push rods on the front if you want a cleaner look. Having the slats split so top/bottom open separately like pic below is also good if you want privacy without shutting out light from the top. High gloss shutters also reflect light into the room and shutters seem to go with any look, period or contemporary.

We've recently had full length curtains in our bay window and a matching Roman blind at the small window. Our small window is not on the same wall as the bay, but it looks really good. We splashed out on made to measure and it was worth every penny.

Hi Susie, you said above that you are going for a Roman blind and wanted some advice on the fitting. Below are some points to consider. You can buy Roman blinds with various backings. As this is your bedroom, ensure that it definitely comes with a blackout rather than a dimout backing. If it is surface-mounted (i.e., outside of the window frame) then less light will appear down the two sides of the fabric. If it is recessed, you are likely to experience more ‘light ingress’. You can choose to have it manually-operated (e.g., via chains made of plastic or metal beads) or remote-controlled (via mains or rechargeable batteries). Although a powered blind is more expensive, it is rather fun to operate it from the comfort of your bed. You can even have it opening and closing automatically at sunrise and sunset (or at other periods) via a timer that knows your longitude and latitude, or from abroad (for security reasons) via a smart phone if you are into technological living! Joy.