ugh, there sure are a lot of people throwing out 'use ESXi - it's free!'. ESXi only runs on certain hardware, so if you don't have that hardware, it's not even a valid choice. Real management of ESXi is not particularly wonderful without using VMWare's management software, and that's not free, as far as I know.
I agree that performance-wise, it's a better choice than VMWServer. But I don't think the entry point for ESXi is as low as xen or Citrix's XenServer. XS runs on a wider range of hardware than ESXi, and the 'basic' management tools are pretty good, and also free.
I agree with everything else you mention, though, so don't think I'm trolling your post. I read TFA, and wow... where to start?