I use a Bontrager Packable Event Jacket now which I LOVE, but it doesn't have a hood.
I'm off to Canada at weekend and will be doing quite a lot of hiking so after something very similar but with hood.
Breathable (I really like Event fabric based on my Bontrager)
Preferably with pit vents
Not too bothered about pockets, simpler the better
Price - hopefully around £100
EDIT: longer at at the back so can be used on the bike