Steak is grilled. Prime rib is roasted whole (usually rare) and then sliced. A grilled slice of roasted prime rib is called a Delmonico steak. Ribeye is a slice of raw prime rib grilled.
A T-bone and Porterhouse are the best value/cut of of steak. Especially the porterhouse. It contains an entire sirloin strip on one side, and a strip of tenderloin on the other (similar to everyone's fillet's they like so much).
It's also important to get a steak that's thick and short instead of thin and long. The thickness holds in the juices, making it keep it's flavor as well as being able to hold for a few minutes after cooking. Thin...I call them "Ponderosa" steaks... need to be ordered one level below what you want it cooked at. If you want it medium, order it medium rare. Steaks cook for 5 minutes after you take them off the grill, so thin steaks will be further cooked on the way to the table. Extremely thick steaks, like fillets, often have to be ordered one level ABOVE what you like (ie medium should be ordered medium well), but this depends on where you're getting it. YOu can always have it recooked if it's not done enough, but if it's too done you're screwed.
The best place to get a steak is somewhere that cooks then with a searer. This is a big device that resembles those pressers they use in laundrymats. It can cook a steak within 10-15 minutes and makes them very tender and juicy. Some of the more fancy places sear their steaks in seasame oil, peppercorns, garlic infused oil, and I know of at least one place that uses citrus oil, which gives the steak an exotic Mandarin flavor (they serve it with grilled mango and papya slices too....it's not bad!).
Never get your steak well done. You'll notice most places will take no responsibility for a well done steak...that's because by the time they're that done, they're shoe leather. If you want no pink, get roast beef! Order your steak no more done than medium well. If you add the 5 minute rule to that, you'll have well done by the time it gets to you.
Hope this is helpful. I'm going to go get some steaks tonight
Fritzo
Former Professional Caterer