Security and dual booting/running in VM Windows and Linux

[Lisi <lisi.reisz@gmail.com>]

I have no metrics myself against which to measure this.  I have Googled, but 
have found it difficult to distinguish the FUD and biased/inaccurate 
information from the "real" - and reliable - information.  I would be glad of 
some opinions from the list.

If I set up a computer to dual boot Windows and Linux (specifically Debian 
Lenny) does the fact that Windows is sharing the computer in any way 
jeopardise the security of the Linux installation?

Does it make any difference whether they are in separate partitions on the 
same disk or on separate HDDs?

Would running Windows in a VM from Linux make the Linux host less secure than 
dual booting, or more so?  Would the Linux host in fact be more/less/equally 
secure than/as it would be if Windows were not on the box at all?

Thanks,
Lisi