Basically need to use SharePoint (because we promote MS yay!) as a content management system for an internet facing site.
How do I get rid of the default SharePoint look and feel and make it look like however I want it to?
I know the process involves creating a new masterpage with SharePoint Designer. However I prefer to code webpages rather than use a visual editor. Is this possible? Do I need knowledge of .NET?
Just check out ferrari.com for a very well made redesign of a SharePoint site.
Does the EULA allow you to disguise the fact that it's MS software?
Remember, you didn't buy the software, you're just paying for the privilege of using it.
Heather Solomon's Branding SharePoint series would be a good place to start. There's a lot you can do just with CSS, JS and HTML, but the most complete solutions (like Ferrari) require some pretty extensive customization with .NET and other SharePoint development techniques (features and delegate controls, in particular).
Your branding effort will be a lot easier if you only need to heavily brand the public-facing "publishing pages", from which you can remove most of the SharePoint-specific elements that make branding difficult.
Also, SharePoint Designer has a source view if you don't like the visual editor.
Yes it is possible to make it look like however you want it to (as you've seen from the Ferrari site). However to create that sort of site takes a lot of work.
Microsoft recommend the use of SharePoint Designer for 'designing' pages and layouts. However changing their behaviour almost always needs Visual Studio and development in .NET. You can largely avoid SharePoint Designer (which may worth considering as it can be a PITA) with an open source tool such as SPVisualDev. Use this with WSPBuilder for packaging your solutions (and avoid VSeWSS where possible).
Considering it sounds like you're just getting started, be aware this is a big topic with a reasonable learning curve. Read a good book on the topic such as Professional SharePoint 2007 Web Content Management Development: Building Publishing Sites with Office SharePoint Server 2007 by Andrew Connell. It takes you through most things you will encounter from the ground up.
I'm working my way through Real World Branding by Andrew Connell at the moment. It seems like a good demonstration, with code.
Plus the Heather Solomon articles as suggested by dahlbyk are always informative.
Just changing the theme, or creating a custom theme for the site, can go a long way towards making SharePoint look a lot better. It's also a lot less intensive then changing the master pages.