Speaking of ground planes, I usually have this high resolution UV'd plane that I made a while back as my ground plane. The plane also serves as my "I'm Bored" relief sketch book so I've created a ton of different morphs for it in ZBrush. Comes in handy for just about any random scape or backdrop etc. that I need.

Guess I'll sort all of those morphs out neatly one day and share them as an INJ for my HiRes Plane freebie, like I said it's my multipurpose sketchbook for the time being.