Has the BTX case died?

Died for the most part. Intel brought about BTX to help cool their horrible P4s. We don't have a lot of chips anymore that get that hot, so no reason to make BTX things.

Unlike the move from AT to ATX, BTX is nothing more then ATX parts that are upside down more or less. The BTX motherboards are the biggest difference. Electrically, BTX and ATX are the same.

I also believe that the motivation for creating BTX
was a lot of ignorance by Intel's staff concerning
the real cause of all the "PressHot"-related overheating:

http://www.supremelaw.org/systems/heatsinks/warning.htm

After confirming the defects in Intel's stupid push-pins,
through empirical, scientific methods, we found this
$5 part that even allows Prescotts to overclock without
overheating:

http://www.sidewindercomputers.com/lgbowiscsp.html

Lastly, if you look at recent developments by Cooler Master
and their many imitators, standard ATX systems can be
very efficiently cooled with proper sizing and placement
of cooling fans e.g. in the top, left side and bottom panels.

The latest CM Storm Sniper comes to mind:
we have one and we love it.

I believe that simple things were also overlooked by
Intel's BTX creators e.g. the "stack effect" that results
when hot air rises.

Live and learn.

Nevertheless, I do believe that some of Intel's engineers
need to re-learn Occam's Razor: the simplest solution is
the best solution.


MRFS

The motivation for my question is if you were building a new computer today would you but a BTX case?

No. ATX and simply get a good CPU cooler. These seem to be tower coolers at the moment. If your really worried about temps, make sure your case has good air flow. And that doesn't mean lots of fans. I cringe when I hear people talk of having 8 fans in their case. How in the h3ll is that flow?

Eight fans do seem a little excessive.

I can however see 7: the four that are in an Antec 900 for example, CPU cooler fan, fan to cool RAM, and fan to cool motherboard chipset.