That's an Oxymoron really, most "professional" cameras are bigger and heavier than their Consumer or Prosumer relatives. As for what is the "best" it totally depends on what you are planing to shoot and where. Everyone has a favorite make and model to recommend so expect a million different replies :-)

Hi Bill I thought I would give you my two cents and see if it helps any. My Dad is a BIG TIME Street Rodder and I spent my entire youth going to car shows both inside and outdoors. So I learned a few things dragging cameras to them for 30 plus years.

Since your new to this try setting an auto mode like Scenic as opposed to something like Portrait. Scenic mode will offer a deeper depth of field which will render images that are more in focus from front to back. A Portrait mode would tend to have a more shallow depth of field and either the front or back of the cars will be softer assuming your shooting at angles (most car shows require an angle shot because the cars are parked close to one another). Another good tip for shinny cars is to use a Circular Polarizing Filter which will tame some of the reflections and totally improve the quality of your outdoor images.

For indoor shots like in a large Convention Center you will probably need a flash to get some fill (light up dark or shadowy areas)especially if you want to shoot the interiors of the cars. Get the correct flash for your camera (the popup flash usually is not powerful enough and is hard to diffuse) and just go with the TTL (Through The Lens) automagic mode to start with. You will start to deal with harsh flash results like "hot spots" when the light hits the shinny cars and it takes some experimentation to "soften" the light. There are inexpensive "flash diffusers" that fit over the flash that will help but there are way too many to list here so spend some Google time and find one you like (I prefer the Graslon 4100D).

Overall you can get some very nice shots using the cameras fully automatic modes but as you grow you will want to achieve "more better" results and for that you will need to transition into either Shutter Priority, Aperture Priority, or fully Manual modes. They allow you to "force" the camera to take the image the way you want it to as opposed to the way the cameras preprogrammed algorithms decide to. I recommend that you pop by a Book Store and look for one of the many books on Digital Photography for beginners and start the journey. Have fun learning, that's the coolest thing about photography is there is always something new to learn (and there is always a new thing to purchase haha). Hope this helps.

Lisa, I'm betting that you want dramatic, larger than life photos like you see in Sports Illustrated and the like? If your shooting out at 300mm with good daylight you should be able to use either Shutter Priority Mode or Manual Mode to get your Shutter Speed up there. If you are looking for tack sharp images in sports you need to keep your shutter speed up there in the neighborhood of 1/640 sec. or higher to freeze the action. By using Shutter Priority or Manual modes you can choose a faster shutter and adjust the Aperture accordingly to get the exposure correct. Another thing you should consider is a Monopod to help keep your rig steady. With no Image Stabilization you can introduce a small amount of shake even with the best hands that will effect your clarity when cropped down. Remember to fill the frame, stop the action, keep the ISO as low as the ambient light will allow to keep noise under control.

As for Basketball games now your starting to see why the "pros" spend $5K plus on a lens. In order to get good clear images with low noise you need a fast shutter and a low ISO. Unfortunately to obtain those two settings requires a larger aperture and those lenses cost the big bucks. In general to get these shots (without an overhead mounted strobe) you need to use the fastest shutter the ambient light will allow and again adjust the ISO and aperture accordingly. White balance can be achieved by experimenting with your cameras settings since some have settings for different lighting. If not then study your manual for the procedure to set the W/B manually at the event your shooting. It usually involves focusing on a white object and taking a shot while in a special mode. This "teaches" the camera what white is under the current lighting.

The best advice is to shoot shoot shoot and then shoot some more. Try varying your shutter, aperture, and ISO to see what the limits of your particular equipment is (to your eye) and make notes of what produces the shots that you are looking for. Then under similar circumstances you have a baseline of where to setup and then adjust as things change. Hope this helps give you some ideas and good luck.