Walter, as others have told me, perhaps April 2007 is not a good time to be trying to decide.
As for open source- I've said a number of times that I'd prefer to stay in the MS camp. That's a personal preference: looking at a few other options is technical curiosity that will hopefully underpin my personal preference. ;-)
Though I'd have to say that php looks really good and I can't help but note that the very latest consumer/small business devices (e.g. Linksys SPA400) have open source (Asterisk, Linux) firmware under the hood...
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1