Total Commander

Three clicks to select a line? Why stop?
4 clicks - select a paragraph (3ple click in MS Word, for ex.)
5 clicks - select all (mouse alternative to Ctrl+A)
It's a joke rather than suggestion. Whole line - yes, I support, but hardly something further.

@Alextp and @Ch. Ghisler

Thnx to both of you.

I still think it is usefull, i am a power copy/paster and will need it a lot.

Dark One pointed out, you just have to drag the cursor vertically from the beginning of the line to select to the beginning of the next line, just below.

i knew that, but tripple click will save (me) a lot of mouse movements.