I use both a colon and an equals sign, depending on the exact effect that I want and the frequency of smiley type over the span of the conversation, but I rarely use a square bracket to close off. I picked "=)" because that's my favorite kind, but I would say that I use "" just as often. It really depends if I know that it's going to make an emoticon or not; I know that neither of the ones that I just typed will become emoticons, so it wouldn't really matter to me at the present moment. I have emoticons turned off on msn, which is my main instant messanger service, which means that I don't have to worry about looking at ugly emoticons, but some of them (such as ":'(") I try to avoid altogether due to complete and utter ugliness. Err, I think too much?