When we first got Winston, we got a 4 by 4 Xpen. He did pretty well for about a week. Then he discovered that he could pull the nice vinyl cloth that we put down under the xpen... he could really have fun. Well, by the time we get home the nice square xpen became a mangle mess.
So we went back to the pet store and exchanged it to a big crate (big enough for a full grown lab). Winston loves his space.

It's big enough for his bed and toys. Good luck with the process... have fun preparing for your baby. Keep us posted.