If you're looking for other suggestions (and assuming you're looking for long distance wildlife), here are a few more toys for your list:
A good tripod or three. I've got a nice Gitzo carbon fiber 3-series for my general use, a Gitzo monopod and a Kirk Mighty Lowboy for macro and low-to-the-ground stuff. A solid tripod is important for long exposure shots (I love night shots), for fast-moving subjects this is less important since your shutter speeds are much faster. One of the most important things to learn about support is that no one bit of kit will solve all your problems. The longer you shoot the more stuff you'll collect and you'll figure out which ones are best for which occasions. On the plus side, support is mostly transportable between brands. You'll need plates that are custom to the camera and/or lens, but they're comparatively cheap.
A good ballhead is indispensable, I really like my Markins heads. I've got a Q3 on my monopod, an M10 on my Lowboy and a Titanium M20 on my 3-series. I've also got a Wemberley Sidekick Gimbal mount which is paired with a ballhead and a long lens (like the 80-400mm I mentioned) to provide a nice, smooth tracking for birds on the wing.
A decent teleconverter is also nice, it can cheaply turn your 400mm lens into 600mm, 800mm, or even 1200mm with only minor quality degradation. IIRC, Kenko TCs are not only cheaper than the Nikon ones but also behave better by passing through more contacts to the lens electronics.
Depending on what you want to do you can also get pretty clever. Set up some lights mounted to a tree and a motion detector to trigger the camera and you can grab some interesting shots. There's a ton of gadgets of various shapes and sizes, I've always been tempted to work with triggers for shooting things like water droplets or lightning.