your short term memory is mediocre at best – deal with it.
If you've got a bright idea while you're on the phone, write it down. Immediately.
If you've got an important thought while browsing the web, write it down. Immediately.
If you've got a sudden intuition while you're at the beach, write it down. Immediately.
There is a clever toolset designed for this task – it's called PenAndPaper. No, really using pen and paper has some huge advantages over iPhones, Blackberries, iPads and the like.
– You don't have to leave the application you're working with right now.
– You don't have to search for the application
– You can use it while you hold the phone to your ear.
Oh, and it doesn't run out of batteries and even survives coffee spills (albeit at the loss of some legibility if you keep on insisting on using these antique fountain pens)
Therefore, dear Michael: Get back in the habit of almost always carrying a minimum amount of paper and a pen.
P.S.: But of course putting it down on paper doesn't eliminate the need to consolidate the notes at some place – in your case I wuld recommend something electronic, virtual and distributable. Like a plain textfile. A text based mind map might also be in order as long as it really helps and doesn't come in the way.
P.P.S: Oh, and since you're such a keyboard fan – as long as you're on a 'real' computer and can acces your notes faster via a the keyboard that by reaching for pen and paper (e.g. -, “Scribbles”, or -, “Scribbles.txt”, ) I guess it's OK to use that instead of paper…