What's the proper way to handle the tab when a group goes out?

Separate tabs.

An even split, and make it clear from the outset so you don't get the "but I only had the entrée and dessert" complaint.

Most of my friends will split it between them, because they don't seem to care when they've had one too many and really love each other more than anything in the whole wide world!  It maybe not be until they sober up that they might object that this or that person didn't pay enough :) There are a couple of us who don't drink so we have separate tabs, however we normally end up as the norminated taxi service for the rest of the mob!
I think as long as everyone knows how they are paying before the meal then there shouldn't be a problem

I really don't worry about it. Whatever others want to do is fine. I would rather pay a few dollars extra than haggle over who had what.

My friends and I usually do separate tabs. I know restaurants don't love that, but the days of one person paying for everything sometimes seem a little old-fashioned. Occasionally one of us will cover it if the rest of us have cash and quickly pay for it. Even split happens sometimes too. 

As a general rule, we split the check evenly between all of us after adding the tip because most of us order within the same price range and consume the same number of drinks.  If someone not usually in our group orders something that's particularly expensive or has more alcohol than the rest, they usually offer to pay more.  If they don't, I wouldn't make an issue of it the first time, but if it happened a second time, I would bring it to their attention and ask them to kick in more money.

I have no problem saying that I need my expense on a separate ticket when I go out with a bunch of people on dutch basis.  If the server has attitude the tip will reflect it.  Once about six of us  went to dinner and when we told the waiter we wanted individual tickets he said he could not split the ticket more than half of the table, so I told him fine, we would all sit at separate tables.  He turned red and asked that we not do that.    If a bunch of us go out to a high end restaurant one of the guys will pick up the whole thing and settle up later. 

My friends and I normally get separate checks. If it's a birthday dinner for one of us, the group will pick up that meal and split the rest evenly. That's the only time we do that. It doesn't make sense to pay more or less for something you did or didn't order.