Just wanted to let everyone know that Silverstripe can work really well with the HTML5 Boilerplate framework: http://html5boilerplate.com/
I just used it to create this site: http://quintessentialcool.com which was recently added to the community showcase (thumb it if you like it!)
I recommend this for anyone who really wants to feel like they're starting a Silverstripe project with a clean slate on which you can build a custom design.
Oh, I also make use of the media "screen" attribute in the link tags in the HTML head to achieve a somewhat responsive design optimised for iphone. Again I found this was also easier to do when the site started from a clean slate.
Let me know what you think.