Well, now that the legendary beast is finally announced, i guess the 100-400mm II is next on my list.

My own current setup:
- 6D
- 16-35mm f/4 IS (my most recent purchase)
- 24-105mm f/4 IS
- 70-300 f/4-5.6 L IS
- 24-70 f/2.8 II
- 100mm L f/2.8 Macro
- A set of primes: 50mm f/14, 85mm f/1.8, 135mm f/2 L, 200mm f/2.8 L, 400mm f/5.6 L

Purchase plans:
- A second 6D body (when there's a good sale).
- 100-400mm II (whenever it comes out).

Later wishlist:
- Maybe a 1.4x TC.
- A Tilt-shift lens or two would be nice.
- Maybe a wide-angle prime?
- Maybe the rumored 11-24?

I briefly bought a 24-70 f/4 IS, but then returned it due to annoying focus-shift issues. Maybe i'll buy another copy someday.