I like the idea of a guy being called Meredith because it is a traditionally male name, and you should keep it if you like it anyway. But it might make it harder to pass because there are a lot more female Merediths than male ones these days.
I like the idea of keeping my birth name (Kim) because it's traditionally androgynous and I'd rather not deal with the hassle of changing my name. I've met guys named Kim in other countries, but, unfortunately, not in the one I live in. At least for my generation (my dad has a male cousin named Kim). I don't like the name and don't think it suits me, but that's how it goes with names, I guess . . . So I'm kind of on the fence about this one.
I might get it legally changed from Kimberly to Kimball. No one's ever called me Kimberly, Kimball is a family name, and it would be similar enough to avoid too much confusion.