I think You should choose PHP,My Sql for web development as it is easier for a new user like you and also provide the flexibility of working in a Cross Platform Environment. But It will be better to chose J2EE if wants more security and reliability as well as flexibility of working in a Cross Platform Environment.But it is vast. If you are willing to use Windows as OS then No other Can Give you better performance, working satisfaction then Microsoft .NET technology.So If you are a windows man go for .NET.

Can I use url like http://abc.com/test.aspx rather than url like http://localhost/test.aspx or http://127.0.0.1/test.aspx while testing my asp.net code in a PC not connected to any network.