Tools in the toolbox is a phrase I use a lot when I talk about learning technologies. The basic message I want to get across is that there's no imperative to use these new tools but you should at least know about them. I've been mulling over whether I can stretch this metaphor.
If you have a toolbox (which I don't really) I would guess that you would want to know how all the tools work. For any DIY job you don't necessarily need to use all the tools but you can make an informed decision about which tool to use if you know how they all work or at least what they are and what they do. As time goes by new tools come out and you have to adapt because that's how life works. Often new tools perform the same functions as the old tools so they act as alternatives. So learning about new tools is a fact of life. For education the toolbox is the toolbox for learnign design and the tools are the ways the educator can deliver the learning.
I will probably soften this slightly if ever I voice this metaphor so that it's less threatening but I think the bulk of this could be a useful way of explaining where learning technologies fit into education.