Running Vista RC1 on just a laptop at the moment, a huge improvement over Beta 2. Have Beta 2 on a 2400+ Athlon and not very impressed with it, RC1 is massively improved.
I have a horrible feeling that Vista will be very expensive, we will see.
Tempted to try RC1 on a spare BP6 out of curiosity.
Incidentally I still run a BP6 24/7 as webserver, mailserver DNS etc.