Does anyone know if there's a way to use Quicklook in Open/Save dialogue boxes? E.g. I'll be attaching a file to an email, and just before double clicking, I'd love to just give a quick press of the space bar to double check it's the correct file. Seems obvious but it doesn't work.

Perhaps there's a third party extension?

You get a preview in the info window and if you realy want you can get info and it is a little bigger.