As a commuter, the leather jacket has been invaluable to me. It enables me to pack less and I don't look like a serial killer when I'm on trips in civvies with only my overcoat available.
It is expensive, but I purchased mine 6 years ago and it still looks great. If you commute and can stomach the initial expense, I highly recommend it. Even if you don't commute, as stated above it is quite warm and much more comfortable than a blazer and overcoat. Good luck!
AT