Minecraft 13w43a, Minecraft 1.7
Windows 8 64 bit
I'm not sure what else is needed, so there are a few things:
HD 5770 graphics card
Core 2 quad q8400 2.66 Ghz cpu
The sides of the cactus item texture are not connected to each other.
I've only noticed this at the creative inventory.
It's not showing up always, hover the mouse around the decoration block page for a while.
The texture of the cactus block seems to be ok.
I think it's first appeared at snapshot 13w43a, but I'm not sure.
Sorry for my bad english... :S