I guess you're set on a flat bar road bike of some sort.

I wouldn't say that you need to make disc brakes a priority - any disc brakes in the price range you're looking at aren't going to be light, and they're going to make the bike you get overall probably have worse componentry. (I'm guessing the price point you're looking at is around that of the giant seek).

Disc brakes are relatively new in the cycling world... and remember people have been cycling for years without them in bad weather.

you just have to learn to ease up when you're cycling in the rain or snow or whatever, give yourself plenty of time to stop & take turns easy. I'm not saying that they aren't great, I just am not sure you should really make them a priority.

Do you have a place indoors to store your bike when you're commuting to school with it? If not, you might just want a junky bike to use for commuting, because getting your bike stolen will suck. It looks like you have a target bike from your blogspot, which should be fine for biking a couple of miles to school...

Look at some of the jamis bikes, they're usually fairly good for the money. Maybe look at a surly cross check if you want to go off road. I know the jamis aurora elite has disc brakes, but it might be out of your price range. You might want to look at some of the cyclocross bikes

If your bf's pretty good with fitting and knows a bit about bikes, he might be able to find you a good deal on a used bike on craigslist.

I don't specifically know anything about the giant seek or the specialized sirrus.