I've worked in both environments. Honestly, the best environment, IMO, is working from home -- office is second. Shared office spaces are a distant fourth.

I'm the type of person who needs a lot of solitude at some times, and at other times, I love to blast music, pace, juggle, and gorge on chips.

When I need the solitude, when I'm in the zone, I don't want you taking a call from your gf, or deciding with some other guys in the office where to eat lunch.

Likewise, I may need to spend 12 hours doing nothing that looks productive. Just kind of thinking as I listen to music and do something mindless like pay bills. I feel like at even the most liberal of open floor plan offices I've felt inhibited if I spent a day or two doing what looks like screwing around. And don't get me started on pair programming.