Wingless,
While I am not a bar visitor too often, I can tell you most gay men have no problem whatsoever with a straight woman being in the gay bars. It just means you have great taste.
Of course, gay men might have more of a problem with straight men... makes "hitting" on them more difficult...
The question is "Are you comfortable with it?" If you are, then do it....
Of course, others may feel different.
William