How many miles do you put on the bike in the average year?
What type of brake pads have you been using and how often do you change them?

I know that rims eventually will wear out but a wheel per year seems excessive. Using softer brake pads (I like the Kool Stop salmon pads), cleaning them often, and replacing them before they are worn out are good ways to make rims last longer. I only put a couple thousand miles per year on my commuter and change pads a couple times a year. Brake pads pick up lots of abrasive crap in daily use. Sand, small rocks, and little pieces of metal get stuck in brake pads and make the rims wear out much faster than they need to.

As to your original question, front brakes could be changed to discs by getting a new fork with disc brake bosses. This is easy if your bike has a 1-1/8" threadless headset/steerer. Not as easy if it is 1" and/or threaded headset as it would be harder to find a suitable fork with disc tabs. Rear brake might be possible with a kit from braketherapy.com. In any case, it will get to be an expensive project fast with new wheels, fork, adapter, brake calipers and hardware, etc. And it could very well be cheaper to buy a new bike with disc brakes already on it.

The runny nose thing is hard to get around other than frequent blowing and wiping. As noted above, gloves with the terry cloth backs and frequent cleaning is one way to deal. A face mask or balaclava can also help.