If one has a software firewall, would it be advantageous to disable the XP firewall?
Definitely, otherwise you could run into conflicts between the two, which could do more harm than good.
Echo above. Should not run two firewalls, and, in some cases, cannot. Crashes/slowdowns/alerts etc. (Same rule with resident AV's.)
Interestingly, when I installed Comodo firewall, it automatically has the ability to turn the XP firewall off, as part of its installation. (Only found that out afterwards, though.) I wonder how many other firewalls do this on installing?
Most firewalls(well good ones) disable the windows firewall by default. I know ZA does and I believe jetico does as well.
ZA is the only one I've ever tried that will also re-enable the Windows Firewall after uninstall. Those firewalls that aren't protecting the system during the boot process maybe "could utilize the Windows Firewall" then turn it it off before fully loading their executable.