I love these store apps. The most interesting and promising feature is integration of html, css technologies as well as support for .Net languages like C# etc.
Windows 8 store apps are nothing but those acquired from Windows store and are different from desktop applications. All the store apps runs in a restricted app container.
I’m a web developer and is flexible with html/jscript, xaml/c# apps. I choose xaml/c# if advanced functionality and behaviour are required in my app. Html/jscript apps are simple and quick to develop(you just need a html and jscript files).