I've eaten at Whataburger since it was purely a Texas chain, and I have to say, it has the tastiest, freshest burgers anywhere. I've had bigger, but never better. The fries are consistently good, and you can have jalapeños cut up on any burger you like, which I love. The shakes are great, too.
Pros: Can be a little slow due to customizing orders
Cons: Worth the wait.