What is the best possible server configuration dedicated for muli-site / multi-network multidb and d

Hey, my wordpress multi-network outgrew it's massive reseller account on my main hosting server, and I have setup 2 new boxes side by side on the same switch, just for http://www.xInd.ca and the network it runs with multi-site, multi-dbase, multi-network, a multitude of customizations and other fancy plugins, and high volume traffic and server resource usage.

I am wondering what is the best possible linux distro and configuration for these 2 servers, if they are running absolutely nothing else. One server will run the databases and the other the front end.
I don't plan to use cpanel, as this would be completely unnecessary seeing as how there will be no other accounts running, and nobody but myself and our admins will have access to anything on the server. I have a server admin available if something is out of my league, and I own http://www.StableHosting.ca so you will note that I am able to set these boxes up however I want them, period.

Clearly, this will open some more cans of worms as we go, as we'll be looking at setting up wordpress properly and securely without the standard urls and filenames, etc. Has anyone here setup a dedicated server without cpanel specifically for wordpress?