As I've said here before, I commute 20 miles round trip, year round, in all kinds of weather. I don't commute every day -- last year I commuted 130 days; I skip days when I need the car for something, have a super tight schedule or other commitments, or when I just feel I need a break.
My commute is fairly safe -- part of the route is on a path, the rest is on roads that have a fair amount of bike traffic on them so I feel that any driver on his/her commuting route knows that they are likely to encounter cyclists. I ride at dark, and have a super-bright headlights and tail lights. Still, there have been (I think) at least 4 bike commuter deaths in Seattle in the past two years that I can remember.
I have noticed that I am having many fewer close calls now than when I first started commuting 3 years ago. Unless you believe drivers are getting safer (I don't), I think this means that even though I've always thought I was careful I must be building up more skills in staying out of trouble and staying visible (though I nearly got taken out by a right hook just 3 or 4 weeks ago).
I consider commuting now a core part of my work schedule and exercise schedule. I'd really miss it a lot if I couldn't do it, and if I ever had to change where I live I'd take commuting routes into consideration when choosing a home.