Thanks girls for the input!

I ordered the Descente Axiom Jacket / Vest last night and I'll let you know how it works (although it will not be extremely cool yet).

I am really not very resistant to the cold, I have no fat on my arms so all my layers of protection are from my clothes! It's around 12-15 celcius these days when I go riding and already I am wearing a longsleeve base layer + a longsleeve jersey + often a windshell, and that's for a hilly ride.

I think I really need something that covers my neck. The Axiom looks like it can do that job. I'll review it as soon as I get it.

For the rest (base layers and all) I have MEC, the Canadian equivalent of REI, but I'll make sure I'll drop by REI next time I cross the border to go to Seattle.

Many thanks!