I hope you don't mind my mentioning your names: Gaer explained that he (or at least some people in his vicinity) uses "by me" in this thread. Timpaec used "for me" in this thread. And the version that I most often hear and read is "that's fine/ok with me." I'd like to know which of these three alternatives you usually use. Furthermore, if you have another possibility to add, please feel free to do so. Do you find that "by", "with", and "for" have different connotations and differing influence on the sense of the sentence? I'm looking forward to read your interesting replies.