Beauty could be a lot of things. For me a beautiful website not only looks good but has a great user experience that works perfectly and delivers the results for the client.
Clients come in all shapes and sizes. Some will want to see something tangible for their money - so in this case mock ups and visuals could be required. Taking Mark's response on board, sometimes I am "that designer". I can't see this changing anytime soon. There's a small group of web celebs who seem to think not showing clients any visuals is a good thing. I tend to disagree...
... However, other clients will trust you to lead the way so you can take a more creative steer using mood boards, element collages and prototypes.
Either way sketching out ideas, functionality concepts, wireframing, looking at other sites and apps for inspiration - everything's in the mix regardless of client expectation.
I tend to avoid frameworks such as Bootstrap and Foundation. There are handy snippets to utilise, but I don't want my sites to look the same and act the same. I like to write and test my own code rather than sift through someone else's.
I tend to use Illustrator for mockups and visuals simply because I prefer working with vectors. I can also export retina friendly SVGs from Illustrator too.
I use Sublime Text for code, Codekit to compile my SASS files, Duo , Chrome and IE to preview and test.