Anti-Virus and/or Firewall for OSX Lion

Yes, I know this is just asking to be lampooned with claims like "Macs don't get viruses, etc." but please keep such comments to yourself as viruses do exist and I do not want to find out the hard way how bad they can be.

I've had my Mac for a while now - yes, the .NET advocate here finally got a Mac - but I am still at a lost for a good virus scanner and firewall for OS X Lion. Most of the problem is every thread I find can be summed up as "Macs don't get Virus, don't install any as it only slows it down."

Coming from a PC background, I swear by Kaspersky's Internet Security - a whole security suite with anti-virus and firewall and a few minor tools. I am after something akin to this on Lion.

So far, I have found Kaspersky make an anti-virus for Mac, but I got rid of it as it kept stopping my Mac from rebooting/shutting down (this was back in Snow Leopard so they may have fixed it since then). Since then I have used Sophos.

But I would like something better. Something with a firewall and something that does not take forever to scan a whole hard disk.

Does anyone have any suggestions? As well as keeping my Mac safe when viruses for it become serious, I do not want to be a carrier for viruses to Windows machines. I still use Windows for my .NET work.

My thanks in advance.