In my last 7 years of flying I had only 2 aborted landing. One was because of bad weather conditions, another one was because the runway was blocked by a landing airplane before us.
The latter example is the most typical, and it's usually a case of misjudgment in the relative speeds between two landing aircraft, or the aircraft on the ground taking just a little too long exiting the runway. The tower controller can direct the landing aircraft to "go around" or the pilot can unilaterally make the decision.
A bad weather go-around due to visibility or ceiling in the US is rare, and in theory due to regs, should never happen. Part 121 (scheduled air service, i.e. airlines) operations have very strict conditions under which they can even attempt an instrument approach. Part 91 (private, non-scheduled, non-revenue generating flights) are allowed to attempt any approach under which they are qualified, and therefore may "have a look" at the conditions at the end of the approach. I can't speak to the JAA/CAA regs or those in other parts of the world.
Winds would be an example of weather causing a go-around.