I'm in the same camp with Lee in that I think my client's also like to see a more personal side of me. And I'm okay with that. I also understand Janine's policy as well and I know of other VAs that don't become friends with clients.
What's interesting to me, is that I don't think I've ever sent a friend request to a client but they have always been sent to me. The other reason I have client's as friends on FB is that it used to be (a couple of years ago) that you had to be friends with someone on Facebook in order for them to be an Admin on a business page. This meant that I had to be friends with some clients in order to be an Admin on their page from my account.
And lastly, my clients all tend to be pretty long term, so many of them that I'm friends with on Facebook have been or were clients of mine for a year or more. I think this also helps with my level of comfort in allowing them glimpses into my personal life.
@Darlene- Hey glad I could help you learn something new about how to use Facebook! Now you can hide those updates from Mom that you don't want her to see