Web Layouts

http://www.flickr.com/groups/ilovewireframes/pool/

http://webdesignledger.com/inspiration/18-great-examples-of-sketched-ui-wireframes-and-mockups

960px Grids

http://960.gs/    http://www.spencerstevens.co.uk/grid.psd

http://www.thegridsystem.org/