The following discussion was true up until around October of 2001 when I purchased a Nikon D1X digital camera body. Since that time, I have probably shot only a dozen rolls of film, and I have jumped headfirst into the "digital revolution".
Wildlife Photography Equipment
I shoot Nikon camera bodies and lenses. I chose Nikon for its complete system, outstanding glass, and camera bodies that just feel right in my hands, but I could just as easily have chosen Canon. I would be the same photographer with the same strengths and weaknesses had I chosen Canon. I occasionally have bouts of equipment lust for Canon's Image Stabilization lenses (primarily on pelagic boat trips), but I always seem to recover and I don't think my photography has suffered as a result.
Camera Body: I used an 8008s body for many years. This is still a great body, unless you want to take advantage of the newer "Silent Wave" (AF-S) auto-focus lenses. I now use an F5 body, which fits my hand perfectly and has all the modern "conveniences". I could have kept the N8008 as a backup body, but it still had many miles left in it, so I gave it to a friend who continues to use it daily. I picked up a used manual-focus FE-2 body as an emergency backup and have never needed to use it in that capacity.
Long Lenses: My longest lens is an AF-S 500mm f/4 Nikkor that usually has a TC-14E (1.4x) teleconverter firmly attached. This results in an effective 700mm f/5.6 lens, which provides a magnification roughly the same as a 14x spotting scope. This is on the short end of what is considered adequate for bird photography, but it suits me just fine since I am actually able to carry this lens for a reasonable distance in the field. For larger mammals or when I need to travel light, I use an AF-S 300mm f/2.8 lens with either a 1.4x or 2.0x teleconverter. I think my favorite lens for nature photography is the versatile 300mm f/4. With a 1.4x teleconverter attached, it becomes a 420mm f/5.6 lens, which is perfect for birds in flight. Add an extension tube like the PN-11, and it can be used for close-ups of nervous subjects like butterflies, dragonflies, lizards, and snakes. I often use the 300 f/4 for wildflower images because of the interesting perspective it provides.
Macro Lenses: For close ups of insects, flowers, snake faces (my favorite), and salamander smiles, I use either a 105mm f/2.8 micro-nikkor, or a 70-180 micro nikkor zoom, which is also a versatile travel lens.
Film: I shoot Fuji Provia F (RDPIII) slide film rated at ISO 200 and push processed +1 stop as my primary wildlife film. When I'm faced with dark conditions that require a faster film (e.g. pelagic photography), I rate Provia F at ISO 320 and push process it +2 stops.
Landscape Photography Equipment
For many years I shot landscapes and scenics using standard 35mm gear with wide-angle lenses. However, Stephen Joseph's panoramic images have changed the way that I approach landscape photography. I find the panoramic aspect ratio matches the kind of landscape images that I enjoy taking (mountains, desert vistas, etc.). Stephen uses a variety of both antique and custom cameras that can produce up to 360 degree images. We have one of Stephen's photos of Chaparral Springs and Mt. Diablo that simply blows me away every time I look at it.
Camera: Unfortunately, I don't have the patience (or the skill for that matter), to take up panoramic photography of that nature. However, I have recently started using the Hasselblad XPan camera to produce pseudo-panoramic images that I find to be quite satisfying. The XPan is a relatively-compact rangefinder camera that can be configured to shoot either standard 35mm frames or double-wide (24x65mm) panoramic frames on standard 35mm film. All of the panoramic-format images in my landscape gallery were taken with the XPan. Michael Reichmann's Luminous Landscape web site has a great review of the XPan and some excellent images taken with the camera.
Lenses: I currently use either the 45mm f/4 or 90mm f/4 lenses with my XPan. When shooting in the panoramic format, the 45mm lens has an angle of view that is roughly equivalent to a 24mm lens on a 35mm camera.
Medium Format: I have recently started experimenting with medium format photography using a Mamiya 7II rangefinder camera. This is one of the lightest medium format cameras available and it produces stunning 6 x 7 cm slides (normal 35mm slides are 2.4 x 3.6 cm). I use the 65 mm f/4 lens, which is equivalent to a 32 mm wide angle lens in 35 mm format.
Film: I shoot Fuji Velvia slide film as my main landscape film. This is an ISO 50 film with extremely fine grain and very saturated colors.