If you are cutting cards right now, stop.
Go download Zotero.
You can thank me later.
Seriously though, having cut exactly one card with this, I think that zotero has the ability to save a lot of people a lot of time. It's a citation manager, so it keeps all your citations neat and tidy. Think of how much valuable information you'd have if you'd been using this since day one.
And apparently their next version will auto-sync between computers.
Oh, and hot tip, when you want to copy the cite out to word, use "Chicago Manual of Style (author-date format). It's just about right for debate.
Hot damn, they even have an openoffice plugin. This day just keeps getting better.