I don't close programs anymore either, and I'm male. I do close documents to keep Exposé from getting unworkable, but my emacs usually has dozens of buffers open.
To provide a anecdotal counter point to balance this discussion, I obsessively close windows I'm not using.
I dislike clutter and distraction. If I leave a Twitter client open or IRC I easily get distracted by it, so I'm constantly hitting CMD-W and use Quicksilver to open them when I need distraction. Same with iTunes when no music is playing.
