I think it's all up to you...If you have the room for the trees, you may as well put them up.
We'll probably just have one this year since we have our busy one-year-old. Our first year of being married DW and I put up a live tree in our living room, as we always do, and I got my mom's old artificial tree and put it up in the sitting room. I was excited about having two trees because it was our first Christmas being married and in our new house. :D