Selling a one bedroom condo/home later on is a bitch, either because most buyers want a second room or because they know that when they go to sell it down the road, it'll be a bitch to sell because everybody wants a second god damn room.
Trust me though, you'll use the space if you have it.
When we had a one bedroom apt though, it was manageable. I'd do it again if I was in the situation. I'm used to multiple bathrooms now so that would be hard, but I still wake up to people sleeping on my couch no matter how many bedrooms I have, so whatever.