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.

Html/Jscript based apps mainly aimed at jscript/html developers. These apps uses WinJS toolkit and WinRT(windows run time). WinJS toolkit provides JS classes, helpers, patterns, html implementation of controls etc where as WinRT javascript api provides api to access platform features.

Windows 8 provides WinRT api to access platform core features like networking, storage, media, graphics etc. This api can be accessed from Javascript, C#, C++ and VB.

Example

Windows.ApplicationModel

Windows.UI

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).