I'm a bit of a noob about privacy, but wouldn't preventing people from knowing you're using Tor be pretty important? I know that, among people who know of Tor, but don't know much about it, the use of Tor alone is generally associated with criminal activity, and often conjures up imagery of worse things than just piracy.
If I were to tell my friends I was thinking of using Tor, and I didn't immediately have a good explanation of what I'd use it for beyond "privacy," then they'd think I was into some nasty shit. I'd imagine the ISPs, and anyone else they might give/sell their info to, would be suspicious of anyone logged to be using Tor.