Just a few quick thoughts about my dream jacket. It would

-be very light-weight, and compact when folded
-fit perfectly, allowing free range of motion
-be odor-free and not require laundering; no zippers that don't work or velcro that sticks to anything
-have the perfect number of pockets that wouldn't sag no matter what was in them and would allow for the easy retrieval of anything that was in them no matter the size
-be climate-controlled, adjustable to the wearer's comfort preference
-be highly visible in all possible conditions including fog, pitch black and bright light yet allow you to appear and disappear when necessary
-have the capability to communicate any thought-activated message in any direction, in audience-appropriate language
-be water-proof yet able to block out harmful UV rays; able to withstand and repel bottles, cans, etc. thrown from motor vehicles; bricks from overpasses; bullets and hand grenades and anything fired from an alien spaceship, including x-rays; able to protect it's wearer from hazardous materials

It would be free.