yup, in agreement withe veryone here.
the jacket has to be LIGHT and _not heavy_. the heavy ones make you sweat huge. a light jacket that's rainproof and waterproof is a _must_, and without any fleecey undersides/heavy fabric. pitzips is also a must.
so:
pitzips
rainproof
waterproof
light, no fleece
in this category, goretex and other nylon/poly/neo/etc. cycling-specific jackets are good. the cost will run you at least $130
sd