for resale/rental value keep 3rd bedroom or turn it into an office?

[Tyler Neison]

I'm designing my next primary residence. It's a single story house and the standard layout is 3bd 2ba. I have the option of converting the 3rd bedroom to a den/study for a minimal expense. I work from home and I know that is becoming a lot more common nowadays for others. For the best resale and/or rental value, which design would you choose?