[Centos] OT: firewalls

What is everyone using for a firewall?

I'm currently using www.astaro.com but their recent releases have soured 
me on ASL as a practical solution on my hardware (1.2MHz Athlon, 30G, 
and 256M).  I only have 4 computers going through the firewall wall but 
it's consistently at 50% cpu load.  There is very little network traffic 
(<10k bits per second on the wan connection, < 40k bits per second 
between other internal lans (I have 4 internal lans and a wan))

Basically I'm using it for:

packet filtering,
masq,
port forwarding,
IDS,
dns proxy (only if my internal DNS servers have failed)
smtp proxy
smtp virus protection
smtp spam protection
http proxy (caching)
http virus protection
http url monitoring (via Cobain)
the firewall also monitors a bunch of statistics, etc.

I'm looking for something that is installed, configured and runs.  I 
don't want to be tweaking this parameter of postfix, that parameter of 
the smtp virus protection, etc.  I want something that just works that I 
don't need to play with except for new rules, etc.

I'll pay a reasonable price for a package that I can test to verify 
suitable performance (I'm not a commercial operation, this is just for 
my toys).

At the moment, I'm looking at Gibraltar.  But the community seems 
small.  I haven't downloaded it yet but I'm considering it an option for 
this round of firewall evaluation.  Any other suggestions for inclusion?

BTW, anything like smoothwall that allows wide open outbound connections 
and doesn't support a box with 5 network cards off the CD is not a 
viable candidate.

Thanks much all,

.dn