Well, defining evolution is a bit hard but it's obviously an important thing to do if you want to say whether it happens or not. A lot of ecologists for example might say that evolution is a change in allele frequencies from one generation to the next. For humans, this happens for every new generation so then it's a question of how much. I understand however that you think that humans are not changing as quickly physically as we used to and then I guess you would have to compare. Do you know if we have evolved slower physically the last 100 000 years than we did the 100 000 years before that? You are also focusing on morphological and mental traits, but what about all those genes that you can't really tell that easily?
Evolution is a process of cause and consequence where those who are fittest - those who pass on their genes the most - add more to the human genetic makeup for the future and those who don't pass on their genes, well .. they don't! There are many ways to be fit, but to put it into some kind of perspective, I can make a simple example :
Imagine that there's a plague which kills people, for example cholera. The chances of dying from cholera is quite high, but if you have a specific genetic mutation, your chances of survival are much higher. The reason is the mutation causes a slight change in some ion pumps in your stomach cells which normally just renders these stomach cells less effective and people who have this mutation have more irritable bowels. However, when they are infected with cholera, the same mutation protects them somewhat from the harmful effects of the cholera bacteria which also have an effect on the operation of these ion pumps.
Before cholera occurs, most people don't have the mutation because having it has a slight negative effect on fitness. Diarreah doesn't make people pass on their genes more successfully after all .. But after cholera has occurred, people who had this mutation were much more likely to survive and then the mutation did add to their fitness and did make it much more likely for them to pass on their genes. The occurrence of the mutation after cholera has taken place in the human population is much higher than it was before. The genetics of the human population have changed somewhat and now they are more cholera resistant on the whole than they used to be - there's been some evolution taking place. Because the mutation is not beneficial in a cholera free environment, the frequency of that mutation might change again in the future until it's as rare as it was before the first cholera plague.
The example should be reasonably simple to understand. For a while, there's one selection pressure (cholera) which favours one trait (a mutation). When that pressure is gone, the trait is not favoured anymore. The point is that evolution of specific traits and most likely the sort of changes you are talking about happens as a response to selective pressure. What the pressure is and how strong it is varies with where you are in the world, what your situation is. Different genetic makeups do well in different environments, for different sexual preferences, diseases and so on. Evolution is just a consequence of natural selection. It doesn't stop when it's reached some sort of goal!
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