Yesterday’s post triggered this question: how to export a chart from Excel to PowerPoint? The short answer: copy the data not the chart.
Standard Excel charts are ugly, they have the wrong formatting, they have the wrong colors, axis labels are in the wrong place, data is not rounded up and too precise. Copying and pasting an Excel chart into PowerPoint is also copying all that ugliness. Even worse, copying and pasting it as a picture might make it look blurry.
I believe that data charts in a PowerPoint presentation deserve careful attention and need to be designed by hand. You start by inserting a blank, ugly, PowerPoint chart into your slide, next copy the data across from Excel and then start tweaking until it looks perfect.
Once you have done one, you can use that PowerPoint chart as a template for other charts in your presentation.