The beef in Argentina is out of this world. I've had expensive steak and cheap steak in Argentina...but never bad steak. Their beef is just different and it's impossible to describe the quality. It has to be experienced. My suggestion: Go to Buenos Aires and find a tenedor libre (buffet) in a touristy section of town. Make sure that steak is on the menu. I went to a real nice one that cost me 4 dollars with a drink. I had a couple steaks. Oh yeah.
Also try to get down to San Carlos de Bariloche. This is a great little town in the middle of beautiful Southern Argentina where you can really experience frontier Argentina. It has a romantic feel to it.