Well, MS have said that Windows 7 may not be ready in time for Christmas 2009, which implies to me that (even if it's not) they are really intending to push it out. So, If you are happy to wait 18 months, that's what I'd do.
From what I am hearing from beta testers, it really is going to be what many of us were hoping for from Vista. And, as far as I can tell, it will use the same driver model as Vista (it's the change to the driver model which is the biggest problem for hardware compatibility).