This is my little starter kit. I use it when I have to work a a website (so pretty much all the time) as a base to start quickly. It contains several folders, here's what they do :
That's the frontend development bit, Html/css/js and all those stuff happen in here.
Design happens in there, contains few psd for my color schemer (yep I love color schemes), that's supposed to be imported in the design psd for easier use/modification of the colors.
Also contains several .psd for font testing and grid systems. Those have to be updated as there's the same psd twice or something like that.
Useful for testing fonts in browser to pick the best size and contrasts before designing with Photoshop's creative font rendering engine. No surprises, I know how it'll look in browser before avoiding the "damn it all looks bold in Firefox" moment.
Sitemaps, Wireframes, whether I produce them myself or not, I like to have all those things in my project folder so I know where they are when I need them and they're archived with everything else for future reference... Better than looking through my emails or any kind of project management software.
Used for backend dev, I put all the files in there and point a local URL to there so, once again, all the code is at the same place.