A little old, but a reference for waterproof/breathability ratings:
Info taken from the backpackinglight forum:
Waterproof/Breathable Specs: UPDATE on 01/20/2011 15:39:52 MST
WATER BREATH
PROOF ABILITY
MM G/M 24HR
Gore-Tex Pro 2L [HTML_REMOVED] 3L 28,000 25,000
Event 30,000 22,000
Gore-Tex Paclite 28,000 15,000
Eddie Bauer Weatheredge Pro 20,000 25,000
Lowe Alpine Triple Point 20,000 20,000
Marmot MemBrain Stata 20,000 20,000
Moutain Hardwear Conduit 20,000 20,000
Norrøna 20,000 20,000
Montbell 3-layer Breeze Dry-Tec 25,000 15,000
Precip 15,000 12,000
Eddie Bauer Weatheredge Plus 10,000 10,000
Columbia Omni-Tec 10,000 10,000
Entrant DT 10,000 8,000
Pertex® Shield® DS 2.5L 10,000 7,000
The OR Helium is Pertex Shield 2.5L. (If anyone has a newer table please post it.)
"The song of a bird…We used to ask Ennesson to do bird calls. He could do them. How he could do them, and when he perished, along with him went all those birds…"-Return from the Stars, Stanislaw Lem
"We just walk around, and sometimes we go out and dance, and then we listen to the environment."-Ralf Hutter, Kraftwerk