RE: key to yank text at point into minibuffer?

[Drew Adams]

    > (BTW, everyone should have a key bound in the minibuffer to a
    > command that erases the minibuffer. I use `M-S-backspace'.)
    
        ** New command `kill-whole-line' kills an entire line at once. By
        default, it is bound to C-S-<backspace>.

Sure, that's fine. There are also other commands (some bound by default) that, 
just like `kill-whole-line' clear out all or most of the minibuffer in most 
contexts. Whatever works and is handy...

BTW, the minibuffer content is rarely more than one line, but it can be.