Hypersonic business jet anyone? The next UKAR party plane perhaps?
I expect this has been discussed on here somewhere but I can't find it. However pie-in-the-sky the actual ideas are, there are some pretty cool looking pictures to look at!
Oh, and what could very well be one of my very best aviation photos right at the bottom. 
What I didn't know until reading this was that 'hypersonic' refers to speeds over Mach 5, currently limited to 'just small experimental vehicles' (they clearly haven't met my dad's 25 year old Peugeot 405 estate then...)
The potential is incredible obviously, but the cynic in me can't help but wonder if we'll ever really see 'manned' travel this fast, mainly due to the ridiculous costs which must be involved - who is so tight for time that they need to get across the globe in a few hours? Surely if you need to be somewhere that fast, even now, you Skype (or whatever equivalent).
Maybe for disaster relief or, of course, military use.
But commercially, even on a tiny scale, I can't see it. Be pretty cool if the technology did develop that far though (although again, you'd have to argue whether the money would be better spent elsewhere) - imagine the flypast at RIAT "now, from your le...oh, sorry".
