I have set up almost all of my bills to be due on the 10th-15th of the month. The few that I couldn't set up that way are either fixed monthly charges or give me the billing amount by the 10th of the month. So, my checking account is large in the beginning of the month, and I make my last payment by the 15th of the month just large enough so that at the end of the month I'll have roughly $100 in the account. Some months it goes as low as $50, some months as high as $150.
The "extra" goes into my mortgage or into savings as needed. There is no reason for me to have any extra in a checking account.
If I have a sudden emergency, I put the charges on a credit card or pull money from savings. In fact, the majority of emergencies in the US are $500 or less (most car repairs, most insurance deductibles) and the vast majority are $2000 or less (major engine or transmission repairs, high deductible insurance, or even a furnace replacement). I never see the reason for people keeping more than that in checking. If $2000 won't cover virtually any emergency that you can come across, then you don't have the right insurance plans.