Hi Steen3d. Welcome to the forums.
You'll get different advice from different people, but my preference is to start with a blank canvas and only use the code you need. That way, you also understand your own code, rather than having to trawl through a lot of stuff you don't need, don't understand and/or need to alter or override. (For mine, using a framework is like trying to assemble a new house from a pile of building rubble, which is harder than starting with new, fresh materials.)
Still, the boilerplate has a lot of interesting stuff in it, and it's worth picking through it to learn tips and tricks and maybe extract useful, reusable bits. (You never know what you'll find amid building rubble. )
Just noticed a new post on SitePoint that may shed some more light on the boilerplate: http://www.sitepoint.com/introduction-html5-boilerplate/