There are different styles that they use on the Food Network. One type is a probe thermometer. That is the kind I use. It has a probe which you stick into the food. That is attached to a readout by a long thin wire. The probe stays in the food the whole time it is cooking. Here
is an example of one. These are really handy as you can set a target temp and the unit will beep when you hit that temp. I love mine and use it often. They run about $30 or so.
Another type I often see on the Food network is a much more expensive kind. It is a particular thermometer called a Thermapen
. These are very fast and accurate, but much more expensive, around $90 or so.
The candy thermometer you described is perfect for candy and deep frying. The other thermometer you described is good as well. both of those are very inexpensive, but do what they need to do.