We have both a joint account - which the bills are paid from - and separate accounts for our own spending money. For us this is the best of both worlds - MrEH's salary goes straight into the joint account, and a transfer then comes out for his personal cash directly to his account. Mine goes into my account as there is a bit more variability on pay dates - and I then transfer my contribution to the joint account, retaining my personal cash in my own account.
We also have a cashback credit card - technically mine but he's named cardholder on it also so we see this as joint. When the statement comes in we both transfer any personal spending that's gone on the card in the month into the joint account and I transfer to the card from there, along with the joint expenditure.
For running a household, having all the "household" spending coming from a central pot makes it far easier to keep track. You end up with an account with just lumps of income, and then Direct Debits or standing orders out again, making it far easier to track what's gone where.
I'm afraid I have to disagree with those who will attempt to infer that if you don't have just the one account with total transparency on who spends what, down to the last penny, there is some form of problem in your relationship. At the end of the day it entirely comes down to what suits the individual couple - I don't feel the need to check on every last penny of MrEH's spending, nor he on mine, whereas others might feel that they need 100% transparency. Horses for courses. Personal money is just that - I save a far higher proportion of mine than he does, he buys more mars bars than are probably good for him, but each of those things comes down to our own decisions.
One very important point if you choose to go down the separate accounts route however - should anything happen and one of you dies unexpectedly, the other will find themselves temporarily having to fund everything from their own account as the deceased's account will be frozen....that can be a very good reason to have things for household bills arranged centrally. We none of us like to imagine that this could happen, but it pays to be aware. The very last thing most people want at a time when they are dealing with the trauma of the loss of a partner, is to suddenly get a call from the bank to say the mortgage payment has bounced...