Like a lot of posters in here, I was the guy who wouldn't be petty with the bill at all, I would just estimate what I owed, and pay more than enough. But having been in too many situations where everyone throws their money in, only to have someone holding the cash saying "uhh, we're about $10 short, plus there's no tip", and then everyone stands there staring at eachother saying "well I know I paid enough" just rubbed me the wrong way.
This may sound cheap, but after being screwed so many times and knowing that friends at the table know they're cheaping out, I've changed my way of paying. Now I pay my share plus tip, put my wallet away, and then if we're short I make a point of finding out why we're short. Then the person who shorted kind of feels cheap and has to get his wallet back out.
The worst was one time at BP's with only 3 of us. Our buddy only racked up $10 on our bill, so when we we're done he said "you guys give me the cash and I'll go pay on debit". So me and my buddy gave him enough cash for our portion plus a $5 tip each. So he comes outside, and the waitress comes out right behind him and says "hey guys, you're a dollar short". So basically our buddy took our $10 tip to pay for his $10 portion of the bill and left, but wasa still a dollar short. So now we're all standing there looking like cheap idiots, who had to be chased by the waitress.
I don't do this with everyone mind you, just a select group of friends that tend to have shortages happen a lot when we go out.