My vote goes to the Gnat.
We have to think of small, cheap and PLENTIFUL aircraft so we can maintain a command of the skies over the UK......
With missile technology being so dominant, all you need is a delivery system loaded with missiles and the agility to out perform any opposition.
Stuff a Pegasus in and you've virtually created a small Harrier - best of both worlds, no runways, fast and nimble and jink out of the way of any incoming...
It IS a dream, innit?