Best Hosting Company for Large/Growing Sites?

If someone asked you what might be the best option for a webmaster who's starting a site that is going to keep growing, what company would you suggest?

Is there a company that offers unlimited space (or at least like 200-300 GB)? And it would probably need some nice bandwidth, too.

I don't know what other info one might need to know in order to make suggestions like this, but think of a website like YouTube, always getting bigger due to never-ending uploads, or a site that offers large downloads (not that YouTube is not a website that you can download from, ha, ha). ;)

Thanks.