One of the things I rant and rave about the most is the bio on websites. I think the tendency for most photographers is to make it a resume and so they go on and on about all this photo stuff that (IMHO) the client doesn't know or care about it and all it does is create a separation of your world and theirs.
I think a bio...actually...I think a (service) photographers entire website should be about who they are and what they do should naturally flow through.
Today I came across OSP's lovely Christina Louvierre's website and it has an awesome bio so check it out! ...and wish her a happy birthday too!
My advice - Think of your whole website as a bio.