What Stack for a scalable video site?

If you were creating a site, with similar functionality to youtube (this isn't another clone, it just has a segment with similar functionality). What stack would you use to be able to develop and allow for scalability?

Basically, I don't want to do the work building it, only to find when I have x number of users online that I have to scrap everything to allow it to scale.

I'm mainly a .Net dev, so if a scal开发者_C百科able solution can be created from that, it would be ideal.

My biggest concern obviously, is the bandwidth. And finding a way I can write for a single server now, and easily add more.

Suggestions? Thoughts?

You deal with the bandwidth issues by using a service like Amazon S3, etc to host your videos. They can easily scale to handle higher loads.

If you're a .NET you should look at the Azure cloud, that is designed to be a scalable .NET platform.