Depends on the car. If it's a performance car, I look at the induction system. If it's a daily driver or a tow vehicle or work truck, I look at all the fill caps and dip sticks to see what the "hassle factor" will be for routine maintenance.
Second thing I look at on a performance car is the front of my pants. If the hood's been open for at least a minute and I don't have a woody, I close the hood back up. Nothing more I need to see at that point.