If you are an ultralight hiker, I have found that Equinox' Gazelle Ultralite Anorak works great - weights 6.7 oz and has covered ventilation areas (flaps) - they only have men's sizes - I'm a women's medium and size small works great
http://www.equinoxltd.com/the-gear/u...ite-anorak.cfm
As for my pants, I also have Equinox' Full Moon Ultralite Chaps, 3.2 oz
http://www.equinoxltd.com/the-gear/u...lite-chaps.cfm
Both of these come in their own little stuff sack. As I said, they have both worked well for me and if I needed a bit of extra warmth, I just wear an extra layer underneath them. My other rain jacket is Patagonia's Torrenshell Jacket, 12.8 oz (I bought it before I bought Equinox) - also works very well, but mine is in bright purple and I look just like barney when I wear it
Good luck!