New Mac with Old PC's: Which way to Network

I'm hoping someone can point me in the right direction on this question, didn't seem to find the answer after searching through the forum.

I just ordered my first Mac this past weekend (iMac) and it should be here by the end of the week, so I'm preparing for the conversion, such as transfering files, network settings, etc. I currently have two PC's, a desktop I use, plus a laptop PC my wife uses which uses it's wireless card to hook up to the network I've set up.

I plan on keeping the desktop PC as well, basically for my college ages kids to use, since they only know how to use PC's and only use the basics. My question is this: Should I use the Mac as the Host or the PC as the host? From a firewall perspective, would the Mac be better at blocking potential hackers, with the PC firewall and router firewall kind of taking care of any other "holes" in security. I know I will keep Anti-Virus on all 3 computers for that peace of mind, but want to get an idea on what others have done for their home networks where they have Mac's and PC's? I'm using a LinkSys BEFW11S4 model (yes, pretty old, may upgrade) and the Mac should be in by Friday, so I want to get everything taken care of this weekend so I can start to play on my Mac and let the kids fight it out over the PC.

Thanks again for any feedback and love the information out there on this site.

Your routers firewall should be all you need.