I was an early adopter of the G1 (have had it one year now), and my phone is rooted with a Cyanogen mod on it. I really like the Android OS, and intend to stick with it.
I would like to upgrade to an Android phone with a faster processor and a physical keyboard, so I am very interested in the droid. In the process of my research I was very happy to stumble upon this forum. I will be watching carefully after the droid's release to see if it gets rooted, and more importantly, if there is a stable rom(s) available for it, such as Cyanogen, who as someone mentioned, is the recognized King of modders for the G1.
If the droid can be rooted, and if stable roms become available for it, then I will likely cancel my contract with T-Mobile and jump to Verizon to get the droid. If there is no rooting and/or stable roms available, I will not be interested in the least in the droid, and I will wait to see what advanced Android phone with a keyboard that T-Mo might come up with later. It is that important to me, for all the advantages others have mentioned in this thread, and for one more reason I didn't see -- Cyanogen's mods give you 5 home screens instead of the OEM 3 home screens, which I find just adequate for my most-used application icons, widgets, and so on that I keep on my home screens.
Fingers crossed for successful droid rooting and stable roms ...