Definitely going now.I think they're worthwhile in the sense you get a better idea of a) all the firms out there; and b) who you are competing against. Any questions you have you can ask, and you can also get a 'feel' for the culture of different firms/organisations and see which one suits you best. And there's free food.
Oh damn, would have loved to meet you but it looks like I can't make it anymore.ps. Sorry I won't be able to make it on Thursday. Was asked at work but unfortunately I have a track day in Marulan.
[EDIT 2:30pm] Looks like I might be there but I'll be a bit late at 6pm. Hope to see some BoSers!