Having been a dad for a little more than 2 months, I recently thought about this as well.
I am not fond of "cute" things myself. Also, in my experience, as soon as they start distinguish between their two ends, kids vastly prefer dinosaurs and robots to fluffy bunnies.
My kid's room isn't decorated yet: he's unlikely to notice, and besides at the moment he sleeps in a cot in our bedroom - my consort is nursing, and that makes night feedings easier.
But in a few months we'll be adding some science-y or space-y stuff (stars, planets, rocketships and such), and some brightly coloured geometric shapes. We are also thinking about painting one wall with a chalkboard paint, to let him express his artistic side in a controlled space (and hoping he will use it instead of other walls).
The consort, being an unrepentant nerd and a trekkie, is quite happy with this.