I was having a similar problem to Jasmine so was happy to find your suggestions about the LWJGL situation. I found the following article on MinecraftForums. It says that it is outdated for current versions of Minecraft, but thought I'd give it a try for Hexxit, which is still in 1.5.2.
I went through all these steps which was pretty easy. Out of curiosity, I launched my vanilla 1.6.2 game (actually modified with Forge, Optifine and a few HUD type mods, nothing major) and it launched and played just fine. I deleted the technic folder and started with a clean install of Hexxit. It did get past where it was crashing previously (finished loading FML and validating my Minecraft account and just closed all windows) and opened to the splash screen. All graphics were upside-down and backwards.
Just for grins, I clicked on the Singleplayer (or reyalpelgniS) button and it went to the next screen:
I thought I'd continue to play along so clicked on Create New World. At this point it was non-respsonsive. Didn't crash the app or my machine, but just didn't allow any interaction. I hit esc and went back to the title screen. Any interaction at this point, including Quit Game, just kept taking me back to the above screen. Switched to Finder and was able to close Hexxit in the dock, no trouble.
I've never seen anything like this. Any ideas? Thanks in advance.