+1 on the Endura jackets.

My Endura Crosscheck (the predecessor to the Gridlock) was a godsend when I started commuting after I moved to Boston last November. However, above 45 its simply too much jacket.

If you're a medium, there is a great deal to be had on the Bay right now on a Endura Gridlock.

Also, the cutter cyclical jacket is another excellent jacket, also made with eVent fabric. Downside is the visibility, but very light and versatile. Much preferred on club rides.