  Since I moved in with J, and he already had power/water/etc, all those bills are in his name. We tracked expenses for 3 months, with me buying all the groceries, toiletries, etc. It averaged out to about $200 difference between what I was paying for misc. stuff and what he was paying for various household expenses.
So now we spend $50 a week on groceries, and I give him $50 a week for expenses, and it works out even. We've had the "money talk" a couple of times. Mainly when he went through periods of little to no work last winter (he's a construction worker). I was basically supporting the two of us, and it was very stressful. We sat down, figured out how much we HAD to spend to keep ourselves fed and housed, and that was it.
It was hard, and there was fighting (should we spend extra money going to the movies, buying new PS2 games, or paying extra on the bills? ), but we got by. We figured out what money we needed to spend, what we needed to save, and what we just wanted to buy. It was during that period that I set up a seperate account just for savings, and started having $10 a week deposited there. 
