My wife and I have a two bedroom home with a large loft that was ideal for a third bedroom. When we found out we would be bringing a little one home I was able to play the part of Dad and build a nursery. This was one of the most rewarding projects I've ever undertaken.
I was inspired by a black and white damask fabric. (It was one of the only patterns we could agree on.) I was also inspired by some stained glass butterflies I found and knew that I wanted to add cutouts in the wall from which to hang them. I really wanted the light to filter in through them.
I will mix anything and everything. I wanted to create this room to be fairly traditional with some whimsical elements.
One thing that my wife agreed on going in to this project was no baby furniture other than the crib. We found a full size dresser at a local store and our friends gave us a Graco crib. Our biggest expense was the nusery chair. We purchased it from a local boutique and it was manufactured by Best Chair. The material for all the bedding was purchased from Babybedding.com and after giving some specs to my wonderful mother-in-law and putting her through a sweat shop session we had some wonderful textiles for the room.
I have three favorite items, the hanging stained glass butterflies, the built-in toychest/bench seat and the built in shelving. I had a lot of fun building these practical elements.
Find one thing that everyone is happy with and build your color sceme and theme around it. Hopefully it will prevent you from being swayed between too many options.