I play on PS3, and had this black screen problem since Beta 4. What happens is that I'll be playing the game normally, and then all in-game environments, characters, etc, goes completely black. In regards to what I'm doing, it's completely random. It's happened in instances, crafting in town, roaming about the wilderness, etc. But the minimap, chat window, hotbar, and all in-game windows are still visible. In addition I can still see names over characters and NPC heads.

The game is technically still playable, it doesn't kick me out, and I can guide myself around via minimap and nametags, but obviously not being able to see anything makes it hard to play.

It fixes itself if I zone, teleport, or return. Logging out also fixes it (but I try really hard not to do this with all the queue problems).