Just to throw out there - wagya is the Americanized version of Japanese Kobe beef, which is much more tightly regulated. You can get wagyu beef that is line with regular high end steaks (which is how some places can sell "wagyu burgers" for $20. True Kobe A5, like what melman was referring to above, is an entire different thing that has a ridiculous fat content that goes liquid and succulent at a really low temp. That stuff is so rich that it's really difficult physically to eat much of it (not to mention the expense).
Not that wagyu is bad by any means - in fact it's some of the best beef you can get in the US (usually), but it's much less tightly regulated and rated like what Japan does.