I gotta vote for the iPod. It has changed my life in ways I could only imagine just a couple of years ago.
Yes, I now carry my entire musical collection (almost) with me wherever I go. I plug my iPod into my car stereo. I plug my iPod into my home stereo system, I plug my iPod into speakers at work. Every once in a while, I break out the earbuds and listen that way!! I wake up somtimes to an alarm from my iPod (and a playlist of Thelonius Monk). I even plug my iPod into my bass amplifier when I want to practice with recorded music. My currnet iPod (my 2nd) is 80 Gig, and currently has just under 12,000 songs on it.