By the time they're old enough to care and appreciate the effort you've gone to they will want Peppa Pig/Thomas/Cars/princesses and all your tasteful planning will be wasted.
So with that in mind I'd paint the room white and...
Buy the cheapest good quality sleep bags (they'll only sick/poo on them)
Buy plain white sheets (same reason as before)
Forget "nursery furniture" because it's a waste of money - buy a proper chest of drawers
Buy plain boxes/baskets to put things in - I like rattan but up to you. If you get plain painted but unvarnished you could stencil on a plain design later.
Neutral carpet that won't show the stains
A black out blind in a plain colour
Plain light shade or better still, a night light.
Then liven it all up with wall stickers and pictures because they are cheap and can be easily changed and a gorgeous blanket for the cot/bed. Try Laura Ashley, Zara Home, JoJo Maman, White Company, John Lewis, local baby boutiques or even EBay, Amazon and Etsy/Folksy (but just check there's no buttons or similar that can pulled off and choked on). No need for even a hint of pink.
About 2 months after the baby's born you may want to get a mobile for over the cot or changing mat. I can almost guarantee you will want the most garish one that plays music because babies have terrible taste and all you want is a good distraction for them!