Look, PHP is much more popular if you look to quaniity in websites, everybody knows that. However, PHP has low enterprise adoption in comparison to Java and .NET. If you plan to work in or with large companies in the coming 5 years (optimistic caluclation - it's probably closer to 10), you are much better off if you are a .NET or Java shop.
That might be very different in 5-10 years, as PHP IS coming along strongly. However, Java and .NET are ALSO making bold moves, so predicting the future here is pretty much impossible.