Summer/Winter Wheels

For something around the 30mm depth I'd not bother with carbon, I'd go for something like CXP30's.
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+1
You'd want the braking surface to be alu anyway. a carbon fairing is just going to weigh more than a deep section alu extrusion. If you dont want the depth for stiffness, and spoke count (ie. youre not that heavy). A medium depth alu rim is probably your fastest option anyway.

These....

http://www.zipp.com/wheels/101-clincher/#

I wager those Zipps would out perform a budget 50mm in all conditions.