m5jay
I purchased my 2001 M5 September 7th for MSRP, as have most people in the last few months, (especailly since 9-11).
I'm not aware of many differences between the 2000 and 01/02 cars, with the exception of a better and larger Nav display.
If the 2000 is the color you want and has the options you want, $65K is fair (for a dealer). I've seen a few used 2001's here in L.A. lately for $68-69K.
For $65K, I'd expect to get a full, 100 mile warranty from the dealer, but all in all, it's probably a fair price.
Check out the other threads on this board, (there's a new one about pricing), as this board and it's members are a huge help. You'll find all the knowledge and support you could possibly want in regards to the M5.
Good luck and hope you become the happy owner of an M5. It's a fantastic automobile !