Don't do "two accounts" as such; do a personal regular account, just like you had before, where you have your real friends/contacts through the "friending" process, and then create a "Page" where /anyone/ can just hit "Like" to become a part of that.  They'll get any updates and such you post there, without being cross-matched to your real friends account.

Remember that "normal" accounts have a limit of about 5000 friends anyway.

An example "page" - http://www.facebook.com/#!/SKelby vs. his "account" - http://www.facebook.com/#!/profile.php?id=573712462

As for keeping two different things up - you can manage writing vs. blogging vs. staying in touch with friends - same thing.  Public posts to the public page, and if there's nothing to say, there's nothing to do.

Hope that helps.