My girlfriend does exactly the same thing. I wonder if its a gender thing? Her PC kept freezing, but she loves her new Mac Air.
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.
I'm also using about 6 gigs of RAM, but since I have 8 to play with, why not? :)