I season my burgers just like i do a steak. make the burger, then right before it hits the grill, some smoked kosher salt ,fresh ground black pepper , a touch of onion and garlic powder. Same when you flip it. Cook to your liking.
Here in Texas we use Tony Chacheres Creole seasoning on burgers a lot, but as mentioned, smoke is a great flavor enhancer as well. I'm not a big fan of the Kingsford charcoal smell to my smoked meat, but I do like it on chicken and burgers.
Hey Bruno, I second that. I started using Tony's back in the early 80's when someone gave me some and I had to mail order it. That was before all the stores around here started stocking it. It goes in just about everything we cook, even have my wife using it in everything. One of the worst things that can happen around here is run out of Tony's. When I smoke ribs I have to do several versions, one is dry and spicy for #2 son and one grandson. I use Tony's.