If you are going for warmth only I would go for one of the windsurfing wetsuits that basically blocks out the wind (surfing suits don't really do this too well)
However, the windsurfing suits aren't the most flexible, so if you want a good combination of flex and warmth I'd go for the warmer surfing suits like the Billabong Solution Gold or the Quiksilver Cell suits (4/3)
I have both the Billabong and Quiksilver suits - my Quiksilver suit is a lot warmer and the blind seals don't go open like they do on the Billabong, so my vote is with the Quiksilver
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