Thanks for the nice tip, I didn't know this before.
What I used often is left double click to copy the value to clipboard.
Since Now there are so many nice python plot libs to choose from, I tend to use gnuplot to get a quick overview of the data, just use:
$>: gnuplot -e "plot 'data.csv'; pause mouse close"
Quite simple yet I can examine the data interactivily, and I can even export it to vector format.
To that task, I think Gnuplot is Unbeatable.