How do you protect the bike from getting too f'd up by snow/sand/salt? I've seen the words "frame saver," but I don't know what that is or how to use it or where to find it. What else is important to take care of?
The thing is, I just bought a bike that is relatively new off craigslist. It's an 07 bike, originally purchased in July. I bought it to ride in the winter, and I keep telling myself that it's a good thing, but I still feel a little bad.. I dunno, it's a CX bike, so it's made to be ridden in dirt and muck and all that, but I guess I feel like I should show it some love.. What can I do to assuage my guilt?

I beleive frame saver is for steel frames and it is sprayed inside the frame. Regular maintenace and clean the bike will do the job.. I polish mine with car wax but I have heard people using furniture wax. For the componets you can use some WD40 as a water displacer, not a lubicant. I don't think you need to do much more.

Start by converting it to SS. Other than that, fenders will help keep the engine clean, lube the chain on a regular basis, clean the abrasive crud off of the brakes and rims periodically, and be aware that it takes more time to stop and start in snow.

Basically, keep the bike relatively clean and you will be fine.

Yup, frame saver is for steel frames. If yours is aluminum, don't worry about it. You want the sand and grit from gunking up your bb, but since it's relatively new, it should be greased ok although you may want to take a look at it after winter to clean and re-lube it. Same w/ the hubs. Clean and re-lube the chain as necessary.

Grease the heck out of your bearings, and apply a layer of grease on points where water/grit could enter the bearings, like where your fork meets the steerer tube. I just learned that one the hard way.

I rebuilt my BB, wheel bearings and the pin wheels on my derailleur with a lot of excess grease in the first two items. When it warms up, I will rebuild my headset.

My bike melts off at work everyday, and I occasionally hose it off there too, being careful of where the water goes- I froze my rear d cable once.

I lube my chain alot when it is sloppy (like yesterday and today) otherwise it starts to skip. I started using wd40 instead of the expensive lube I use on my road bike.

I plan on thoroughly cleaning or replacing my chain in the spring. I will also rebuild everything again, and wash the bike.

Fenders are a must, having a wet butt and skunk stripe sucks as do wet feet. I like the Planet Bike fenders, with mudguards, they were a big improvement over the fenders I had before. Get full fenders with mudguards, short fenders or snap ons help, but not enough. I really believe this to be the biggest issue if you are going to be riding in inclement weather.
I also like packing the heads of every bolt with grease (stem bolts, water bottle bolts, all the brake bolts, deraileur bolts etc). If left untreated they'll rust in no time flat (standing water in the heads) and make the bike look junky. Also lube the chain frequently.
I guess washing the bike would be nice too but that's going to happen when it crawls a few degrees above freezing here.
If you have a choice I think disc brakes are better, I'm stuck with rim brakes and some days they really don't work very well. However, if you are missing the tabs or the wheelset isn't disc ready, I wouldn't worry too much, just make sure they are in good condition.
Does anyone have a suggestion for good pads for v-brakes, for riding in rain, sleet, snow, etc? I've been thinking about something like the Kool-Stop multi compound pads https://www.jensonusa.com/store/produ...+Tectonic.aspx but I don't have a local source for them, anyone know if they are good?

Thanks for the advice (and for assuaging my guilt ).
It's a Binachi San Jose, so it's SS (actually, I'm running it fixed, but whatever) and it does have fenders.
There is no way that I am taking the thing apart! I will take it to the shop in the spring and have the LBS relube/replace parts as necessary, but some stuff is just way over my head...