Yeah, there's a million things you can answer on that topic. I've worn gloves for years. I've been riding bikes for years and years even all-year round. (I've even worn a snowmobile helmet and ski pants in the winter.)

First, I know you may be thinking mountain bike, but if you haven't thought about it, there are hybrids as well like the GT Traffic 3.0. I find mountain bikes give you a more forward position that gives you a lot of control in the winter. However, I also find it puts a lot of weight on your hands/wrists. I've ridden 10-speed road bikes in the 1970's and 80's that I just did not like as far as riding position, comfort and maneuvrability goes. I think hybrid bikes are way more comfortable and give you a choice to just coast around in the streets or go through a park if you like. Right now I have a cheap mountain bike from Canadian Tire for biking in the winter, a hybrid for doing groceries etc. And I'm planning to complete my build of a touring bike with a Nashbar frameset after x-mas.

You can look at Shimano's website for information on the levels of quality. But in general, I think it goes something like Tourney, Altus, Acera, Alivio, Deore, Deore LX then XT and XTR which can be kind of expensive. Even though some people like SRAM and Campagnolo, I find if some replacement parts aren't as easy to get or more expensive, I don't bother, I'd rather stay with Shimano.

I have a small mirror on my helmet and I find it helps. If I hear a bus, usually I'll look to see where it is so I can toss myself to the side while it passes by. I also have a bell as a polite warning that I'm coming in case someone might be "surprised" by being passed by a cyclist (paths here are cyclist/pedestrian).

When I bought my last bike, I actually went around everywhere trying them out to see how they fit me. I'm almost tempted to tell you that if you've never ridden a bike, you might be better off actually to start with cheapy to see what you like. I mean you have grip shifters, indexed thumb shifters and friction thumb shifters. In reality, I think it would be cool training to start with a real cheap one with thumb friction shifters (in other words, non-indexed). I once had a job where I placed a lot of stuff on shelves and after work when my muscles were tired, I had what felt like electric shocks in my forearms when using grip shifters. I also find they break more easilly. So, the point of trying out a cheap bicycle first is to see what you really prefer in a bike. Then you could examine other bikes to see what kind of parts they have to find out what you like. That would make it way more easier later on to figure out what you'd really like.

One more thing, some people say it's easier to pedal a bike with 700c wheels than 26 inch wheels. I've gone up hills sitting on my seat with a hybrid bicycle with 700c wheels that I had a harder time climbing with a bike with 26 inch wheels. But, I believe for width, the happy medium for 700c wheels even though that's a personal choice, to me it would between 700x37, 700x38, 700x40 or 700x42. Any thinner and you'll feel railroad tracks and any bigger than that and you'll feel slow when the tires are not inflated enough (700x45 are pretty big in my opinion).

Anyway, that's what I have at the top of my head. I could think of others if you had more specific questions.