Ok, the title is intentionally noobish. Please don't disregard my question.

I'm a little overwelmed by the whole web environment. Even though my major is IT/ web development I have only learned enough about css, xhml, asp.net, php, js, and mysql to make me feel like I will never learn how to put it all together. Currently my .Mac page is still the simplest way for me to put stuff on the web. Feature shortcomings not withstanding.

I want to make a website that helps people live green. I know it's been done before but I think I have a unique twist on it that hasn't been done yet. If i can pull it off with an insanely simple UI then I think I might have something that really gives people some value.

I've been following Merlin and 43F for a while now so naturally I returned here for some advice. i think I may be in the position that Merlin was in 15 years ago.

Finally, here's my questions.

How do i go about building the site that I want?
Does it require a CMS?
Will drupal work for a site where a huge database of 'green' facts can be accessed, compared, and presented so that users can make buying decisions? Do I forget all that and buy some server space somewhere and build everything from scratch (CSS,Mysql, PHP, XHTML, etc)?

I'm just lost.