I don’t have a D300 on my wishlist, as I don’t fully utilize my D200. I’m also thinking of trying Canon for my next major camera purchase.
Regardless of whether you use D300 or Canon, Earthbound Light provides a warning about the type of sensor cleaning fluid you use. I gather the D300 has a ‘sensor shake’ option, but it won’t handle the dust that fuses to your sensor–pesky stuff.
However, the regular Eclipse fluid won’t work on the sensor coating used in newer cameras–including the D300, my D200, the Canons, and others–and we should be using the Eclipse E2 cleaning solution. Since E2 works on all sensors, it makes little sense to buy the original fluid.