Angus is not the correct answer. Angus is a breed not a USDA Grade of beef. Any breed could probably be any grade as the grade system is based on quality. What you feed the cattle and how they are tended to will determine the amount of fat, marbling, and quality of the meat.
There are 5 USDA Beef Grades and they are top to bottom as follows: Prime, Choice, Select, Standard, and Institutional Grade. The quality becomes less as you descend in the lineup.
The reason I am spending my time and attention on this is that as this recession we are not having any more drags on and our grocery dollars shrink I want you to know what you are paying for. Then you can spend more wisely.
If I was having a special dinner and wanted really good steaks I would be asking for Choice for sure. Depending on my budget I might even go Prime!!
On the other hand if I was in a money pinch I might consider buying fillet as you might be able to get away with select just because of how very tender the beef is going to be in that cut.
It pays to do a bit of research and find out about about meat grades if you intend to get the best for your food dollars. It also pays to learn how to cook the less tender but very flavorful cuts too!