Izzie has the best of both worlds. My roommate and I just started a new system this week. During the day, when we're not home, Izzie is in the kitchen which is blocked off by a baby gate. She has her bed, toys, food and water there. At night, we started putting her in her play pen. During the day, she needed more room to run around, plus, she was "playing" with her potty pads in the play pen. It was always a nice mess to clean up.
Here is the play pen that I bought for Izzie (about $80 on eBay)
http://www.dogdecor.com/dog-pen-dog-play-pen.html
It's great, because whenever I go home to California, I can take it with me...