I think a lot depends on what stage of the relationship you're at. Is this a trial run of sorts? i.e. if it works out you'll be getting married or making a lifetime commitment similar to marriage, but right now you just want to see if you live together well? Or is this already at the life-time commitment stage? You also need to consider whether you want children.
For couples without children who are effectively living as a friend-share with regular sex, I think it's fine to maintain completely separate finances with all bills split 50/50 and paid either by having an additional joint account to your separate accounts into which you each pay your 50%, or one can simply transfer to the other.
IF you are committed for life, however, whether married or otherwise, all money should be viewed as joint money IMO. It doesn't matter whether you have a joint account, separate accounts, or both, but you should both feel that you have equal rights to that money and be able to access it. It doesn't matter that one person earns more - you are a team and everything should be shared.
The danger with joint accounts is that both parties can buy something the other isn't aware of and push the account into the red. For that reason, I think the best way is to pool the money, work out the bills, and then allocate each other a set amount of disposable income per month which you know you can spend as you want without having to check with the other.
You can choose to have your personal earnings paid into your personal account and then transfer bill money into a joint account, with what's left then being your disposable cash. You can ensure that all bills are direct debit and split them to an equal value between your separate accounts. Or you can have a joint account that all bills come out of and all your earnings are paid into, and you transfer your disposable income to your separate accounts.
There are lots of ways of dealing, but the most important feature is an agreement over your approach to finances, transparency, and equal access.