Welcome, Microsoft. Seriously.
Let's hope that Apple responds to Microsoft's entrance into the digital audio player field with a little more restraint than they did when IBM launched their personal PC. You see, back in 1981 Apple had a commanding lead in the personal computer industry (sound familiar?) and no one thought (including Apple) that would ever change. When they heard that IBM, that old stodgy company that everyone thought was over the hill, was going to start selling PC's they took out a full page ad welcoming IBM (link to the full size version, thanks to MacMotherShip).
We all know how that turned out.
If Apple takes out a full page ad in the Wall Street Journal welcoming the Zune to the market sell all of your Apple stock. I don't think that'll happen though because Apple is a much more pragmatic company now. They did the unthinkable by switched to Intel chips (and sold a boatload of portable machines). They aren't afraid to take a risk and replace a fast selling product (iPod mini anyone?). Heck, they even ported iTunes to the PC (and hell did freeze over). All good signs that Apple is aware that in order to keep the market they need to work at it.
This is why I am not overly worried about Microsoft's entry into the DAP world. I think that ultimately this will force Apple to revisit the iPod and improve it, perhaps adding some things that David wants, and then the consumers (that's you and me, bub) win.