I'm a warm-running soul and find Gilets are the business. I've had a cheap parrot Zati-light which is nearing the end of it's useful life but it's been brill. I'd happily get another and at £15 it's a bargain, but they only have XL in Orange :-(
Probably one of my best ever bits of kit - and it's very basic, mine's nylon with mesh vents.
However, you get an idea from the spec. Planet-X used to do an identical one.
http://www.daleswear...riceHigh&page=1
I have an old
Altura lightweight jkt which I wear instead of or over the top when it get seriously cold or wet. I found it's been a great combination for a wide range of conditions and each fits in the others pocket happily giving flexibility.
The Gilet and jersey or armwarmers can be worn in pretty heavy rain and keeps you fairly warm and relatively dry as long as you're riding.
Worn on a hugely wet FNRttC - 2nd rider:
http://www.flickr.com/photos/29651652@N06/5945923350/sizes/l/in/set-72157627088923419/
https://picasaweb.google.com/108733...qKr7nA6AE&feat=directlink#5629996368589884002
Actually, the photos show different strategies for different folks, some go for full waterproofs, me the Gilet and the likes of dellzeqq wore just their jerseys and it rained most of the night. I rode back to London in the same kit and it was stair-rods!