For creating web application with Metro Style, we have good options compare to creating WPF or pure winforms applications with those complex styles.
Few packages which I have used in my projects are as below –
Bootstrap Metro – http://aozora.github.io/bootmetro/
Metro UI – http://metroui.org.ua/
Metro BootStrap – http://talkslab.com/metro-bootstrap/components.html ( I never used this but hear that its nice too)
Bootswatch – http://bootswatch.com/cosmo/
Metro UI Template – http://metro-webdesign.info/
Hope this helps someone to choose proper , if you find anything really nice which you think someone can use it, please let me know and i will be happy to put it here…