For a really nice looking, elegant one you usually have to spend more than $50. A "mundane" one can be had for cheaper, though.
I remember you picked the 300 to begin with. I'm still really not fond of it due to it's lack of options, but it does fit the bill aesthetically and it seems that's the more important aspect here. Though if you're going for Antec in the price range, the One Hundred would be a good upgrade, IMO. It's a better case than the 300 by far, despite the lower model name:
http://www.newegg.com/Product/Product.aspx?Item=N82E16811129098
The Rosewill Challenger was also in your post, yeah? It's an even better case than those two, for the most part. If you're happy with it, grab it.
If you want to spend a bit more, Cooler Master's 690 II is a good upgrade over both of those in build quality and functionality, and looks great as well. Very professional looking, IMO:
http://www.newegg.com/Product/Product.aspx?Item=N82E16811119215
On the other hand, if you want to chop the price a bit, the Rosewill Blackbone is on sale. It's not anything spectacular in terms of features, but it does offer four front USB ports, tool free drive bays, decent cable management if you're good with zip ties, and looks that don't scream "I belong to a teenager!"
http://www.newegg.com/Product/Product.aspx?Item=N82E16811147023
It also has a sibling from Xigmatek called the Asgard II.