- Loose sentences/notes, which I group into 'clouds' of related topics (without a mindmap's edges). Scapple [0] on OSX is good for this (and spider diagrams), and Microsoft OneNote.

- Spider diagrams - I find mentally these much easier to create when listening to a presentation or in a meeting. The straight lines help for some reason

- Mind maps. My weakest skill, but as someone else commented they stay in the mind better than anything else does, and I can remember some from 3+ years ago.

[0] http://www.literatureandlatte.com/scapple.php