as a poor dc messenger, rain and snow don't hardly cover the wonders of the weather. might i suggest for expanded categories:
(a) rainy spring day:
(b) summer with 80% chance of storms:
(c) autumn with drizzle:
(d) fresh snow cold, windy, sunny day:
(d.5) fresh snow, very very cold day:
(e) cloudy day, melting snow:
(f) the terror of terrors, FREEZING RAIN:
all of these days require different gear. i've only been at this for a year and as i suspect from talking to the many vet guys, wardrobe takes a career to perfect.
here is what i have so far:
an honest to god rain jacket - always bring if there is a chance of rain. ($90 - ems)
2 pair full fingered gloves - if it's snowing or drizzling ($10 supergo)
ski gloves + 2 pair full fingered gloves - for super wet days ($20 campmor)
another girl i met cut larger mittens so she could put them on over gloves and pull them back to poke her fingers out, she even had a key hole in the wrist
arm warmers - always have a pair stashed somewhere dry ($14 supergo)
knee warmers - great for the fall when the temperature drops due to clouds or nightfall. it's not healthy for those knees under 60 degrees ($10 t-town)
under armor cold gear - this stuff is brilliant if the temp is under freezing ($48 city sports)
2 sweaters - a good idea in varied situations ($4 thrift)
a poofy vesty thing - wonderful on windy days to keep your innards nice and toasty
fleece vests are useless, however a sleeveless hoody is a great layer in the cold coldness
i have no experience with wind breaker jackets
running tights - go great under jeans ($15)
winter tights - on slushy days these work great with a a pair of shorts or alone ($50 performance)
rain pants - for fall and spring and winter wet ($20 army surplus)
no snow pants if you are riding a track bike - it's dangerous and ridiculous
ear warmer bands bug me, but are a god send on cold humid days.
a baklava - it has to be really bad to put up with one of these things
1 pair of extra socks per expected inch of rain fall
i personally don't often do hefty socks, i hate hot sweaty feet
i also hate cold numb feet
as far as dealing with wet shoes, i covered an old pair of shoes with shoe goo and wear those booties over them.
i've also witnessed neoprene socks inside of shoes
i've also done the plastic bag thing and it's always a fail
get a front fender (detachable?) it saves a lot of the wet from getting on your toes
and a back one for your bum
i saw a dude the other day with a small tarp butt cape thing tied around his waist
if you know someone who works downtown, keep an extra stash of clothes and shoes there.
also, hook-ups at (a) coffee shop(s) are priceless

these ideas are mainly geared toward those who have to spend all day in the streets of DC, i have no idea what a winter would be like in chicago or nyc. as mentioned earlier i'm now starting my second winter, so i have a lot to learn. truth be told i'm cheap. i bought my ski jacket from a thrift store for $4.50, it's a real gem of the 80's. i've never owned on of those fancy wool jersey things that seem to an indispensable part of a real messengers wardrobe. i come from farming folks who taught me to deal with winter with flannel and carhardts. i'm asking santa for a wool jersey this year. yay!