As long as you have an ATX formfactor motherboard, any ATX case will do. (check to make sure your current computer is atx - If you have flex or micro atx motherboard,youll need a case that can accomodate it) You should look for a case with at least 3 external 5.25 drive bays, 2 external 3.5 drive bays, and 4 internal 3.5 drive bays. (the more internal 3.5" drivebays the better) All of the computers you saw are ok, but I would recommend taking a look at newegg.com. On ebay you'll probably end up spending about 45 bucks after shipping, so it might do you good to look on newegg for a case in this price range with free shipping. Also on newegg people write reviews so you wont be buying blindly.
Here are a few things about cases you should know:
1. Aluminum cases are generally better to maintain cooler temperatures in the case and they are lighter too, but they are not as strong as steel cases. (some aluminum cases feel "flimsy")
2. Power supplies that come with inexpensive cases are generally not top qaulity. Sometimes you'll get a good power supply, but sometimes you wont.
3. Some cases are screwless and come with drive rails or other mechanisms that makes installing drives MUCH easier.
I hope this helps