Commuting - suggestions on bad weather bike components for a new build?

I'm in the midst of building up a surly steamroller for my winter/bad weather bike and was wondering if anyone here could suggest some components that would stand up to the elements. Specifically headset, bottom bracket and hubs. I'm not looking to build a beater, more like a bomb proof weather machine that won't let the elements in. Thanks!

Not sure if there are 120mm spaced sealed bearing hubs, but if there are, get some. I've been impressed with the low maintenenace aspects of new external bearing bottom brackets/cranksets as well.

I built up my Cross Check 3 years ago to be a year round bomb proof SS commuter. My parts choices Chris King headset, ultegra bottom bracket, Surly flip flip hubs. So far, perfect. I am replacing the bearings in the hubs right now before winter sets in, they're getting a little crunchy. But that's all I've needed to do so far. I'm about to cross 6k mile mark on the bike.

Depends on what crank you intend to run on the BB since the frame's a fixie.

-R

i'm actually going to run it single speed. thanks for the comments!