With many thanks to
killabeez for the link, I now give you a
list of specific companies who support SOPA. It makes more sense to target them specifically and indefinitely until they withdraw their support, rather than to indiscriminately put off purchasing stuff for a month.
As such, I will not be supporting any of the companies on that list financially (to my knowledge, anyway, sometimes companies own other companies and you'd never know) until they withdraw their support.