The most obvious reason is the white blanket of snow that covers everything. It's pretty. It covers up all the dead grass and branches, making everything except the side of the road look clean and fresh.
Winter is cold. Sometimes it's so cold that your water pipes freeze, and you have to climb down into the well pit with a space heater or two. The human body doesn't handle these temperatures too well, either. It's comforting to know, however, that if you're cold, you can always put on another layer of clothing. Sure, you won't be able to move, but you're warm enough, right?
Another aspect of winter life is the way it affects your vehicle. As you're driving down the road, the tires kick snow and dirt onto the bottom of your car. Eventually, a big clod of ice forms just behind each tire. At first glance, you may see this as an annoyance, but those of us who have grown up in cold, snowy climates have come to see this as an opportunity for fun. Many of us take great pleasure in kicking these ice clods off - as long as it's not done in our own driveways. In what other season can you do this?
If you're into watching professional sports, you've got plenty to pick from during the winter: hockey, football, basketball, figure skating, skiing, and the list goes on. More ambitious people, who like to participate in sports, can add ice fishing, deer hunting, snowmobiling, snowboarding, and tobogganing to the list, not to mention gathering a bunch of your friends to throw snowballs at each other. Winter is the only season in which you can trick a friend or younger sibling into putting their tongue on a frozen metal pole.
My favorite part of winter is the weather phenomenon known as the blizzard. The temperature may or may not drop, but the wind picks up and the snow falls in large quantities, making it difficult to see where you're driving. "And this is a good thing?" you may ask. Yes, it is. This means you don't have to go to work or school. You can sit around all day in front of the TV, the computer, or on the couchvwith a good book. You can go outside after the wind dies down and wade through the new four-foot-high snowdrifts. You can sit by your front window and anxiously await the snowplow, then yell at it when it hits your mailbox for the third time this month. Blizzards, especially severe blizzards, give you something to talk about for years. Twenty years from now, I'll be telling my kids, "You think this one's bad? You should've seen the Halloween blizzard of '91. Now that was a blizzard."
Winter causes us to slow down and pay attention to things around us, not only when we're driving on icy roads, but in other things as well. With so many people these days running like mad, winter can be a reminder that not everything has to be at a fast pace.
These are just a few of the reasons I believe winter is the best season. And after just suffering through a week of temperatures in the nineties with high humidity, my opinion is even stronger. I'll always prefer winter.