bike commuting

This is probably the most un-tech thing I will blog about but I would like to start bike commuting. I will try to make it as technical as possible.
First things first: the route, then the bike, then parking my bike while at work, then do i need to change once i get to work?
So I move to Oregon from Idaho and the culture is very green here comparatively.
I think I would like to take a part in that as well.  Actually my interest in this is probably more because It would be cheaper than buying another car for my family.
Anywho, I have been on the hunt for a bike.  The only real biking I could consider that I have participated in are taking the family out on bike rides in the evenings and Saturdays.  Still that can be enough when you are pulling a trailer for two and trying to keep up with the pack.
So as you can see I don’t have all the experience in the world, but I am willing to learn and would like to keep up my fitness level as a secondary motive.  In the recent weeks I have looked at probably 30-40 different bikes.  With that being said, looking at bikes is very different than actually test riding a bike.  Everything from a straight up touring road bike to fat tire mountain bikes.  Mostly the bikes that I am interested in are road bikes.
Two drawbacks to this:
1.  Road bikes can be expensive.
2.  Road bikes are usually made for fair weather road riding.
What I mean by fair weather road riding is that road bikes usually have the c-clamp brakes that pressure the wheel hub as the braking mechanism instead of disc brakes which seem to perform better in wet conditions.  I am living in Oregon and so 3 out of the 5 last work days have been rainy.  I would like to continue riding in wet weather.  The campus I’m at has a fitness center locker room where I could clean up once I do get to work, so that is very convenient.
As I have been talking with the different salesmen about bikes, I am starting to get sucked in.  I feel myself thinking about this purchase way too much.  Although I potentially could spend a whole lot of money and turn out to be a very big purchase, it really shouldn’t be this hard.
Here is my dilemma.  My main purpose for buying a bike is to commute to work each day.  The factors that play into this are weather and durability since it will be used daily.  Weather makes me want to go for the disc brakes.  Durability makes me want to go for the more expensive components.  The problem is that road bikes don’t have disc brakes.  This turns me into the direction of some cyclecross bikes as well as hybrid or urban bikes.  That’s a whole story in itself how every other sales guy calls every other bike by his own name and category.
The Scott SUB 20 found at REI is the closest I have come to what I think I want.  I say that I think this because I still am undecided.