Waterfield Designs has released two new slip cases for iPhone, and one in particular has the potential to flip people in the no case camp. Their Suede Jacket is a super-simple, minimalist pouch case with a handy side pocket for your Bluetooth headset. People that don't want a case for whatever reason will appreciate its ability to protect the iPhone from scratches when you toss your iPhone in a bag or a purse.
The Suede Jacket isn't suede but is built from a thin, stretchy mesh material with an optional back pocket that is large enough to securely hold most small to mid-sized Bluetooth ear pieces and plenty large enough for ear buds. When it's empty, it lies flat against the Suede Jacket and you hardly notice it's there.
If you're looking for a more substantial slipcase with extra protection check out the Waterfield Smart Case which fits both the 2G and 3G iPhone.