This is the full text of Owen’s talk at the Responsive Day Out. It makes for a terrific read!
A really nice piece on scale, ratio and rhythms in web design.
An excellent piece by Stan in which he questions (without rejecting out of hand) applying proportion-based rules to the web, a medium with inherently fluid proportions.
A handy tool for calculating grid and gutter widths although you'll still have to some calculating to get the figures to work in percentages (assuming you're designing for the Web).