I guess it depends on what you mean by best. I've used IIS, and PWS, for years and they work fine (generally), and they are relatively easy to set up, and involved to lock down. Apache is supposed to be more secure, but a little more involved to set up (I've never set up Apache, so don't rail me).

The main difference is that Apache starts out locked down, and you have to open up what you want, and IIS starts out pretty open, and you have to lock it down. That is my understanding, at least.

ozzyosbourne hopes he does not get railed on this...