This is my favorite for prime cuts of steak (rib and loin sections). I'm not talking about the grade of beef as I use choice 90% of the time and splurge on some prime for really special occasions. I like it because it really doesn't taste like anything. I know that sounds stupid because why would you use it, but it doesn't make the beef taste like anything else - it just seems to enhance the "beef" taste of a good steak. It's pretty basic but I've had many people ask me for it after eating a steak I've cooked.
3 tsp salt
3 tsp paprika
2 tsp ground black pepper (I like to use the worchestire (sp?) flavored stuff you can find most anywhere)
1 tsp onion powder
1 tsp garlic powder
1/2 tsp ground coriander
1/2 tsp ground tumeric
a dash of ground red pepper only if you wish
I still contend that the best way to make a good steak is to buy a good steak. You can make a good steak turn out bad, but you can't make a bad steak turn out good! Bright white, rock hard, opaque fat - good marbling - and almost a loose texture of the muscle fibers if you can find it.
Topping it off with a good smear of butter doesn't hurt anything either.