Obviously, I'm not a professional photographer.  I'm just a serious amateur.  I take my lessons and buy all my equipment from Mark Comon at Paul's Photo in Torrance, CA.  You won't find a better teacher or a better camera shop.

Cameras 
I'm a Nikon guy and I shoot nothing but digital--haven't shot film since I bought a D100 in 2002.  My primary camera is a now a Nikon D3 and I use my D2X as a backup.  The D3 has a full-frame sensor, whereas the D2X has the 1.5 magnification factor associated with most digital cameras.  The D2X with its X sensor is great for telephoto work;  the D3 with its full-frame sensor is great for wide angle and medium range--and fabulous for sports and low-light photography.

In addition, I have a D200 that was modified by Life Pixel Digital Infrared Conversion to record infra red only, which is really cool.

I also play around with a Casio Exilim EX-S600, and a Leica D-LUX3, so I can take a camera with me everywhere.

They're both terrific little cameras; the Casio was especially useful during our trip to Africa, when I had to travel with the big camera bodies stuffed in my vest pockets.

Lenses
I use the following Nikon lenses: 

Buying lenses is very much like buying speakers for a sound system.  With sound systems, you should put as much money as you can possibly afford in speakers, because the sound will be the best it can be.  If you buy lousy speakers, nothing--not even the greatest receiver/turntable/tape deck in the world--can make them sound great. 

Similarly, you should put as much money as you can possibly afford in lenses, because good glass will give you good, sharp results.  If you buy cheap lenses, it will show up in your photos, regardless of the number of megapixels your camera has.

For example, all three Nikon cameras have excellent, top-quality sensors with huge amounts of pixels.  The 24-120mm is an OK lens and the 18-200mm lenses is a very good lens (cost about $650 each), compared to less expensive, slower lenses, and they both have image stabilization.  But, I can always see the difference in photos taken with the 24-120mm when compared to all the other lenses I have, all of which are f/2.8 or faster and allow far more light to enter the lens for faster shutter speeds and sharper, brighter photographs.

Sure, megapixels are meaningful, but good glass rules.

Telextenders
My dad always used a 2x extender (called it his "doubler") but a 2-power extender eats up too much light.  I have Nikon 1.4 and 1.7 telextenders and they work very well.  I used the 1.7 extensively in Africa; used on my D2X, it turned the 300mm lens into the equivalent of a 765mm lens.

Flash
Neither camera has a pop-up flash, so I have one SB900 and two Nikon SB800 flash units.  (Pop-up flashes aren't very good, anyway.)  The SB900 is a great flash unit that puts out lots of light and has many customizable features, and the SB800s are great for added light and effects.  I also have Nikon's SU800 flash trigger, which fits in the hot shoe of either camera and allows me to control all three flashes remotely so I can position them around the subject.  An item I use a lot when taking people photos, when I can't bounce flash off the ceiling, is the LumiQuest Pocket Bouncer.  It's kind of goofy looking (looks like a French fry scoop) but it does a great job of enlarging and softening the light source.  You never get red-eye with a Pocket Bouncer.  I also use Really Right Stuff's Wedding Pro Flash Arm, which gets the flash further up off camera and makes the light from the flash even softer and more uniform.   

Tripod
I use a Gitzo 1348 carbon-fiber tripod that has four-segment legs so it will fit inside a suitcase.  It has an Arca-Swiss ball head on which is mounted an AcraTech quick-release plate.  The quick-release plate is indispensable out in the field; trying to screw a camera onto a tripod when on a photo trip would be ridiculous.

L-Brackets
I have L-Brackets made by Really Right Stuff mounted on the D3, D2X and D200.  They're marvelously well made brackets that fit the cameras snugly and allow flawless, fast mounting onto the tripod quick-release plate, in either portrait or landscape orientation, and access to the battery compartment.

Camera Bags
Not long after I started getting serious about photography, I realized that my first camera bag wasn't going to cut it.  I shopped for another one at Paul's Photo and Mark told me that I'd never stop buying bags.  He said, "I have camera bags like Sue has purses."  Unfortunately, he was right.  When you get into photography, you find that you need numerous bags to fit numerous different types of trips and/or circumstances.  All the bags I use now are LowePro bags--an Orion AW, a Stealth Reporter 400AW, a Magnum Pro AW, and a Pro Trekker AW backpack.