Call me a plate expert. I own 6 full sets of plates and I've only had a kitchen for 5 years.

It definitely is my second obsession following Halloween. (You should see my Halloween kitchenware collection!)
I can think of two issues with the plates you covet. First is visual. My basic black plates are the ones I have with me right now. (All my others are in storage right now in Tulsa.) I wish, however, that I'd brought the white oval ones with me, even though I'd be more worried about breaking them. Why? Because food just doesn't look pretty on black plates.
I know it's weird, but it makes a difference for me. Check out these two websites:
GreenLiteBites
foodgawker | feast your eyes
The lady on the first website always has yummy, healthy food, but those black plates make it look bland and boring.
The second website is a collection from many cooks, and you will notice that the majority are on white, or lighter colored plates, and the majority are yummy looking.
So if you plan on using these plates as your presentation plates, as much as I love black, I would consider a different color.
I do, however, own a set of cobalt blue plates that are square and they make everything look delicious. But they do bring me to my second dilemma, which may be a problem only a crazy plate collector like me would have.
I have a set of small black round plates, big red round plates, white oval plates, black hexagonal plates, large square blue plates, and small square polka-dot plates.
As you can see, storage is an issue.

None of them can stack on top of the others. Someday I will have a large plate rack, but before they went into storage all sets basically had to have their own shelf. So keep that in mind as well. Do you have enough room to store more than one set of plates?
(I definitely see the interest in the Wal Mart plates, though. I would have a hard time passing them up too! My husband would freak if I brought home another set of plates!)