Ask HN: What rates do you charge (or expect to pay) a top tier consultant?

I've been consulting for around 1 year now working at a rate that I find reasonable. I have been approached now by a much larger client (fortune 500) who I know I could charge more too. What sort of rates could a producer / designer / developer lead with? I don't want to undercut myself. Also should you charge hourly or daily or be flexible and offer both?