I don't regularly bring my laptop home except when I'm working over the weekend or will be traveling. But I have ridden home with it enough to know that if I had to commute with it regularly I'd use a rack and panniers. I love backpacks of all sorts and use them for my daily commute but I don't particularly like my laptop on my back for the whole ride home (25 miles). It's not bad in a backpack for my shorter rides in the morning though. I guess it depends on the length of your commute.