Well, I'm happy to have moved you a "career's worth" of wisdom forward in a single comment. You aren't negotiating with HR. HR does not know what you do, and HR's best idea of what you're worth comes from those ridiculous salary survey sites.
This is a cogent point. HR may be your point of contact for your salary negotiation, but they are not the decision maker or barrier. Ask for more money and they will ask someone else for more money on your behalf. HR is almost never the enemy in less-than-huge companies (and even then only moderately at worst).
