FI and I have been discussing this lately, and I think we're going to combine pretty much everything, but still each maintain the long-term savings we've started. We'll each have a weekly "allowance" for personal expenses, although we haven't really nailed down specifics (this won't be an immediate shift).
We've been living with separate chequing, short term and long term savings, with a joint chequing account since we bought our house, and while it works, it's not ideal. It's a pain to maintain that many accounts and determine what expenses should come out of where. We'll stick with it until I have a full-time job though, because until then, our incomes are really unequal and I'm living partially on savings (being a student = totally lame financially).
So, what do you and your SO do (if you live together, and if not, what do you plan to do)? How does it work? What are the pros and cons? We're not totally sold on combining, but we agree that what we're doing now isn't working for us anymore.