firewall: different box, same box, samebox VM?

[Douglas Tutty <dtutty@porchlight.ca>]

I've go Etch going on my new Athlon 64 3800+ with 1 G ram and 80 G
drives in raid1.

I'm using an old computer as a firewall until Etch is stable.

My old computer could die any time and I want to plan ahead.

The firewall is the last onion layer of my security (home use, dial up,
no publically offered services) and I am wondering about the best way
(not necessarily the easiest).

I want to end up with just one physical box (I don't want to have to
boot up the old slow box just to check email).

Should my firewall be just on the same box as everything else I'm doing,
or would it be worth while doing something like setting up a VM to run 
the firewall?  I've been using ipmasq (shorewall takes 10 minutes to
load on my current firewall).

Other than for running a concurrent MS VM, what other uses are VMs?

I'm using the term 'VM' in a generic sense; I haven't yet looked at what
all implementations there are other than VMWare.

Thanks,

Doug.