Game crashing, fails to open world

The game crashes every time I open a world. This did not previously happen in 1.7.10 - I played on snapshot 14w30c and could no longer load in worlds (either got void or stuck on loading screen, reported as separate bug). Downgraded to 1.7.10, and now I get crashes in all worlds.

Attached 2 crash reports on different worlds, one single player and one multiplayer server.

What I expected to happen was...:
World to load

What actually happened was...:
Game crashes (on any world, single or multiplayer)

Steps to Reproduce:
Open world in 1.7.10