JackNaylorPE :
I'll not build an HTPC / MMPC until I find case with multiple (2 min, preferably 4) exterior Hard Drives on the front panel. An internal HD (twin HD cage in case ya wanted RAID) for the OS and programs and exterior hot swappable HD's for content.
If you are willing to dish out the money, you can get something pretty close like the SILVERSTONE Silver Aluminum CW03S-MT ATX Media Center for $699 excluding shipping cost. Note, that's just for the case without a PSU:
http://www.newegg.com/Product/Product.aspx?Item=N82E16811163106
The case has an exterior hard drive bay and a bay for a floppy drive. You should be able to install hard drive in the floppy drive bay, thus giving you two external hard drive bays. That in addition to the external bay for a DVD drive.
Personally, this is about $300 more than I would like to spend on a case. Then again, if your expectations or requirements are high then you should also expect to pay a price in proportion to your expectations / requirements.
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The case I will most likely buy for my next HTPC is the SILVERSTONE Black Aluminum Crown Series CW02B-MXR ATX Media Center for about $390 + shipping:
http://www.newegg.com/Product/Product.aspx?Item=N82E16811163084
It won't met your requirements since there is no external bay other than for the DVD drive bay. Internally it can house 6 hard drives for a current potential total of 6TB. Underneath each of the two drive cages is a duct which will fit a 90mm/92mm fan to cool the hard drives.
The case itself will be tall enough to install my Scythe Ninja+ HSF which is about 6" tall alone. One of the things I love about this HTPC case is the fact that the rear exhaust fan is 120mm which is pretty rare; actually make that unique for a HTPC case. Larger fans tends to quieter since they do not need to spin as fast as smaller 80mm or 60mm to move the same amount of air.
Another unique thing about this HTPC case are ports in the back to passthrough tubes for a liquid cooling solution if that's your thing. Not really important to me.