The best colors for PowerPoint presentations are those which ideally described theme of your presentation.
Naturally History of Holocaust presentation will be looks idiotic in light pink colors palette as and Tales of Unicorn presentation in dark gray or brown palette.
The best way to find the perfect combination color/theme is to find your theme on PowerPoint templates sites. And search around there and to pick up appropriative color and picture.
If your presentation is for young children or teens, you might use bright colors like fuchsia and yellow. Any color that grabs the audience's attention would do. However, if you are giving a presentation in your office, bright colors might actually be discouraged as they are considered too frivolous. People you want to impress and convince might think that you are not serious enough. About college, it depends on what your presentation is about. If you have to give one on, say, Nepalese culture, you might want to use rich colors like maroon and reds to promote the richness of the culture. If it is about an economic appraisal of a certain industry, you would need to tone your presentation down. That was about it about appealing to your audiences' senses. Now, let's look at the other criterion.
The colors you use (and this should take precedence over making a beautiful presentation) need to be such that the words on each slide are clearly visible. This depends on the amount of light in the place where you are presenting and on the resolution of the powerpoint projector. Visit the place once before you design your presentation. If there is a lot of light in the room, even after drawing the blinds, you should really avoid whites and other pale colors for your text because then they would not be clearly visible.
In all cases, avoid using red or dark blue font on black background because I always find it the least legible. Besides color, make sure that your slides are not overcrowded or the font is not too small. These also aid better understanding by your audience. Remember that if your presentation is difficult to read, people may spend more time trying to figure the words out rather than listening to you. And that, my friend, you do not want!