I think I fixed mine! (got an evening of straight gameplay after usually crashing during or just after log in)
Rig: (it's old, don't laugh, I had kids...)
Core 2 duo, e8400 OC'd to 3.2ghz
GTX460
Asus p5q-pro
4gb ram
win7 home premium x64
corsair 560watt psu

Tried:
reinstall game
old nvidia drivers (clean install)
new nvidia drivers (clean install)
registry cleaning
Defrag
memtest
Thought it could be low psu watts, but EQ2 ran just fine, and problem was limited to FFXIV...
MSI Afterburner (Worked!)

When I opened afterburner to get more info on my card, I found it was running higher than spec's (by a lot) according to the nvidia website. So I downclocked it back to (near) factory specs and increased fan speed to be sure the card stayed cool... and =) Got a full evening of play in.

Today, I logged in and BSOD'd right after log in (no downclock)... rebooted, started Afterburner, clocked things down... and still on 30 mins later. Sure, that's only about 5 hours of testing, but it's a hell of a lot of improvement over my <5 minute sprints on Monday and Tuesday.