Congrats on your new D5000; it is a very nice camera. Keep me posted on how you like it, especially compared to the D300. BTW, the quiet mode is activated through the release screen – it is a Q in a square, but I’m sure you know already.
The X1 and the rumored Nikon counterpart compete, imho, with my D-Lux 4 and not the D5000. They are bit too small for my taste. It is amazing that they put an APS-C sensor in such small body. It all depends on portability, for me. It is the type of camera that I have with all the time.