Just to provide a counter stance:
Go for the den, make it a kick ass library/piano room/kids room/2nd TV/man den/getaway spot
I assume it's either den or bedroom right? Majority of new homes in Irvine, you enter and there's a boring grandma bedroom to the left or right. Then you walk straight to get your great room/kitchen combo. Differentiate yourself with a well decorated secondary space. Add a French door to the den if possible (Maricopa plan 2?).
When the time comes to sell you'll agent will advertise it as a 4th bedroom down regardless if it's a den or a room with a closet