Is there a "best" filesystem? Separate partition good?

[SpamHog]

I am planning a Linux install from scratch,
in view of running xBSD and Win9x as guests.

I can make one or more dedicated partitions,
mounted inside /home/<user>, just for the VMs.

I know that the several file systems available on Linux
have pros and cons for different kinds of usage,
but I have not found a good discussion of their features
w.r.t. laying a VM upon them.

1- Any special criteria for choosing a FS for VMs?
Is there a discussion or document I missed?

2- Also, is there any advantage
(other than a bit extra crash resilience)
in giving each VM its own partition,
or even its own separate drive?

I hope these are somewhat interesting questions....

Filippo / SpamHog
http://filippo.ru.ru