I bought a new machine that is Vista Capable, spent an hour or so installing Vista Ultimate and have had no problems since.
The only hitch was Vista required the uninstall of the Fingerprint Reader and some other HP security programs that came with this unit (NX9450), driver issues I'm sure. These uninstalls constituted the bulk of the install time.
Other than that I've been very happy with Vista, if you have a machine that's capable of running everything Vista provides go for it. It is a bit spendy, but in the long run worth it in my opinion.
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