My continuing frustration: what's the IDEAL environment for WordPress?

So, I continue to fight with LAMP stacks, and now I'm fighting with IIS. So, I put this to you: what's the ideal environment for running WordPress? What pre-packaged distro? What interface, control panel, etc? What RAM footprint? Etc.What are you doing for full backup? What's cost-effective and what's free, and what costs, but frickin' just works?

I have a moderate set of sites, each with about 20-100K impressions a month, so what would you run if you were going to do it in a way that was reliable, standard, and fuss-free?