Hosting questions...need some assistance

Hey all,

I'd like to thank you first for taking the time to read my post. I have a list of questions I'm hoping the hosting experts can assist me with. Here goes:

1. What are the estimated server costs for, say, a fraction of YouTube's capacity?
2. What type of server/hosting environment is suggested for this type of community site?
3. Are there any reliable hosting providers that you would recommend?

I'm currently working on a business plan for a potential project and appreciate any assistance. Thanks again!