re: To upgrade, or not to upgrade...... my video cards....

I would definitely recommend waiting for Haswell-E, because it introduces a new socket, a new chipset, and a new memory standard. The X79/socket 2011 has been around a few years and is basically EOL, though the most recent CPUs for it were released late last year.

If there were an urgent need for a fast performing machine right now, though, I don't think there'd be any severe disadvantages to building maybe one of them with current hardware and waiting until the end of the year or early-mid 2015 to build the rest. The Ivy Bridge-E platform will still last you several years, but there just won't be an upgrade path with the CPU (not that Intel releases major improvements with their refreshes before changing sockets anyway).