Speak up!

What makes a good speech?  I reckon it's a combination of lots of things, but is there one specific thing in a speech that makes it truly memorable/rousing?  'I have a dream..'  is the one being remembered from 50 years ago today and its difficult to put yourself back then, when race relations were very different to now, when mass media meant turning up at a football stadium, and was reported in the following days news (maybe) rather than being transmitted to all and sundry by so many different mediums, all of them near instantaneous. So I think despite Martin Luther King's booming voice, his delivery, the words, his charisma etc etc, the most important thing about his speech was the moment in time - when the 'race question' was getting to the top of the political and chattering classes agenda.  Of course, if I had delivered the speech at that time, no-one would have taken any notice, so it definitely needed many ingredients to create the big effect, but timing is surely the biggest.
If I try and remember specific speeches, I struggle a bit.  There's Brian Hanrahan on the deck of the aircraft carrier in the Atlantic as we sent the Harriers out in the Falklands war - "I counted them all out...then counted them all back again"  I still remember the feeling that evoked in me, hoping he would be counting them all out and back again every time.  And that's it.  I thought I would be able to recall a Margaret Thatcher speech from the 80s, but not at the moment, and even though Tony Blair made quit a few good ones, I can't recall any.  I can see both sincere faces, but no words.
I suppose it's a bit like the Hitler speeches, sounds good, looks good, but in one ear and out the other in no time.

Did my weekly swim last night, missing 2 weeks out in the process. Managed to get 76 lengths in which is about 1.2 miles - half what I'll be doing next July.  The good thing is that I felt like the pull part of my stroke was improving, making me feel like I was faster, even though the clock didn't support the feeling.  Oh well, I need to get the technique sorted first.